diff --git a/app.js b/app.js
index 3bcb09b..6caed63 100644
--- a/app.js
+++ b/app.js
@@ -1,15 +1,18 @@
-const fs = require('node-fs')
+const fs = require('node-fs');
 const sourceFilePath = './sources/tasks.json';
 const stats = {
-    countAllTasks: 0,
-    tasksByDay: {}
-}
+  countAllTasks: 0,
+  tasksByDay   : [],
+  tasksByMonth : [],
+  tasksByYear  : [],
+
+};
 
 // const enableFilterByTag = true;
 const enableFilterByTag = false;
-const filterByTag = "work";
+const filterByTag = 'work';
 // const outputFileName = "work_report";
-const outputFileName = "all_tasks_report";
+const outputFileName = 'all_tasks_report';
 let countExcluded = 0;
 let countIncluded = 0;
 
@@ -17,237 +20,291 @@ let countIncluded = 0;
 console.log(` ### lecture de ${sourceFilePath}`);
 
 fs.stat(sourceFilePath, function (err, stat) {
-    if (err == null) {
-        console.log(`File ${sourceFilePath} exists`);
-        sortTasksFromJson(stat)
-    } else if (err.code === 'ENOENT') {
-        // file does not exist
-        console.error(`le fichier ${sourceFilePath} est introuvable. Impossible d en extraire des infos.`, err)
-    } else {
-        console.log('Some other error: ', err.code);
-    }
+  if (err == null) {
+    console.log(`File ${sourceFilePath} exists`);
+    sortTasksFromJson(stat);
+  } else if (err.code === 'ENOENT') {
+    // file does not exist
+    console.error(`le fichier ${sourceFilePath} est introuvable. Impossible d en extraire des infos.`, err);
+  } else {
+    console.log('Some other error: ', err.code);
+  }
 });
 
 // parcourir les tâches
 function sortTasksFromJson(statObject) {
-    console.log('sortTasksFromJson')
-    fs.readFile(sourceFilePath, 'utf8', function (err, data) {
-        if (err) {
-            return console.log(err);
-        }
-        let dataTransformed = JSON.parse(data);
-        // console.log('data keys ', Object.keys(dataTransformed))
-        if (dataTransformed["contents"]) {
+  console.log('sortTasksFromJson');
+  fs.readFile(sourceFilePath, 'utf8', function (err, data) {
+    if (err) {
+      return console.log(err);
+    }
+    let dataTransformed = JSON.parse(data);
+    // console.log('data keys ', Object.keys(dataTransformed))
+    if (dataTransformed['contents']) {
 
+      countTasks = dataTransformed['contents'].length;
+      stats.countAllTasks = countTasks;
 
-            countTasks = dataTransformed["contents"].length
-            stats.countAllTasks = countTasks;
+      console.log('yes data ! tasks:', countTasks);
 
-            console.log('yes data ! tasks:', countTasks)
+      dataTransformed['contents'].forEach((elem, index) => {
 
-            dataTransformed["contents"].forEach((elem, index) => {
-
-                // console.log('tâche ', index)
-                // évacuer les sous tâches
-                // if (elem['contents']) {
-                //     console.log('content ception, on évacue')
-                //     countExcluded++;
-                //     return;
-                // }
-                // filtrer par tag les tâches
-                if (enableFilterByTag) {
-                    console.log('filtre activé', filterByTag)
-                    if (!elem['drawer'] || !elem['properties']['tags']) {
-
-
-                        console.log('on vire cette tâche n\'ayant pas de drawer :', elem)
-                        countExcluded++;
-                        return;
-                    } else if (
-                        elem['properties'] &&
-                        typeof elem['properties']['tags'] !== "undefined" &&
-                        elem['properties']['tags'].indexOf(filterByTag) === -1
-                    ) {
-                        console.log('on vire cette tâche ayant les itags :', elem['drawer']['ARCHIVE_ITAGS'])
-                        countExcluded++;
-                        return;
-                    }
-                } else {
-                    console.log(' - filtre désactivé')
-                }
-                // après le filtre, on range les tâches
-
-                if (elem['properties']) {
-                    console.log(' - ref ', elem['ref'])
-                    let title = elem['properties']['raw-value'];
-                    let tags = elem['tags'] ? elem['tags'] : [];
-                    let closeDate = 'Indéfini';
-                    let todoKeyword = 'DONE';
-                    if (elem['properties']['closed']) {
-                        closeDate = elem['properties']['closed']['end'];
-
-                    } else if (elem['drawer'] && elem['drawer']['ARCHIVE_TIME']) {
-                        closeDate = elem['drawer']['ARCHIVE_TIME'];
-                    }
-                    if (elem['drawer'] && elem['drawer']['ARCHIVE_TODO']) {
-
-                        todoKeyword = elem['drawer']['ARCHIVE_TODO'];
-                    }
-                    if (!tags.length && elem['drawer'] && elem['drawer']['ARCHIVE_ITAGS']) {
-
-                        tags += elem['drawer']['ARCHIVE_ITAGS'];
-                    }
-
-                    // jour, 11 premiers caractères
-
-                    let day = closeDate.substring(0, 10);
-                    if (!stats.tasksByDay[day]) {
-                        stats.tasksByDay[day] = []
-                    }
-                    stats.tasksByDay[day].push({
-                        todoKeyword,
-                        title,
-                        day,
-                        closeDate,
-                        tags,
-                    })
-                    // console.log(' ' + title)
-                    countIncluded++;
-                } else {
-                    console.log('no', elem['properties']['raw-value'])
-                }
-            })
+        // console.log('tâche ', index)
+        // évacuer les sous tâches
+        // if (elem['contents']) {
+        //     console.log('content ception, on évacue')
+        //     countExcluded++;
+        //     return;
+        // }
+        // filtrer par tag les tâches
+        if (enableFilterByTag) {
+          console.log('filtre activé', filterByTag);
+          if (!elem['drawer'] || !elem['properties']['tags']) {
 
+            console.log('on vire cette tâche n\'ayant pas de drawer :', elem);
+            countExcluded++;
+            return;
+          } else if (
+            elem['properties'] &&
+            typeof elem['properties']['tags'] !== 'undefined' &&
+            elem['properties']['tags'].indexOf(filterByTag) === -1
+          ) {
+            console.log('on vire cette tâche ayant les itags :', elem['drawer']['ARCHIVE_ITAGS']);
+            countExcluded++;
+            return;
+          }
         } else {
-            console.log('no content')
+          console.log(' - filtre désactivé');
         }
-        // console.log(data);
-        console.log('tâches inclues:', countIncluded)
-        writeHtmlOutput()
-    });
+        // après le filtre, on range les tâches
 
+        if (elem['properties']) {
+          console.log(' - ref ', elem['ref']);
+          let title = elem['properties']['raw-value'];
+          let tags = elem['tags'] ? elem['tags'] : [];
+          let closeDate = 'Indéfini';
+          let todoKeyword = 'DONE';
+          if (elem['properties']['closed']) {
+            closeDate = elem['properties']['closed']['end'];
 
-    // les répartir dans des tableaux selon les périodes de temps
+          } else if (elem['drawer'] && elem['drawer']['ARCHIVE_TIME']) {
+            closeDate = elem['drawer']['ARCHIVE_TIME'];
+          }
+          if (elem['drawer'] && elem['drawer']['ARCHIVE_TODO']) {
+
+            todoKeyword = elem['drawer']['ARCHIVE_TODO'];
+          }
+          if (!tags.length && elem['drawer'] && elem['drawer']['ARCHIVE_ITAGS']) {
+
+            tags += elem['drawer']['ARCHIVE_ITAGS'];
+          }
+
+          // jour, 11 premiers caractères
+
+          let day = closeDate.substring(0, 10);
+          let month = closeDate.substring(0, 7);
+          console.log('month', month)
+          let year = closeDate.substring(0, 4);
+          let taskDescription = {
+            todoKeyword,
+            title,
+            day,
+            closeDate,
+            tags,
+          };
+
+          if (!stats.tasksByDay[day]) {
+            stats.tasksByDay[day] = [];
+          }
+          if (!stats.tasksByMonth[month]) {
+            stats.tasksByMonth[month] = {
+              period: month,
+              tasks : [],
+            };
+          }
+          if (!stats.tasksByYear[year]) {
+            stats.tasksByYear[year] = {
+              period: year,
+              tasks : [],
+            };
+          }
+
+          stats.tasksByDay[day].push(taskDescription);
+          stats.tasksByMonth[month].tasks.push(taskDescription);
+          stats.tasksByYear[year].tasks.push(taskDescription);
+          // console.log(' ' + title)
+          countIncluded++;
+        } else {
+          console.log('no', elem['properties']['raw-value']);
+        }
+      });
+
+    } else {
+      console.log('no content');
+    }
+    // console.log(data);
+    console.log('tâches inclues:', countIncluded);
+    writeHtmlOutput();
+  });
+
+  // les répartir dans des tableaux selon les périodes de temps
 }
 
+/**
+ * Retourne un html présentant le nombre de tâches réalisées pour chaque mois
+ * @return {string}
+ */
+function RenderStatsMonth() {
+
+  let months = Object.keys(stats.tasksByMonth);
+  console.log('months.length', months.length);
+
+  let monthHTML = '';
+
+
+  months.forEach((elem) => {
+
+    monthData = stats.tasksByMonth[elem]
+    console.log('monthData.tasks.length', monthData.tasks.length)
+
+    monthHTML += `
+        <div class='columns'>
+            <div class='column'>
+              <h2 class='title is-2'>   
+                  ${monthData.period}
+              </h2>
+            </div>
+            <div class='column'>
+              ${monthData.tasks.length}
+            </div>
+        </div>
+        `;
+  });
+  return `
+    <div class='box'>
+        <h1 class='title is-1'>Stats mensuelles</h1>
+        ${monthHTML}
+    </div>
+    `;
+}
 
 // sortir un html présentant les périodes de temps et les tâches réalisées
 function writeHtmlOutput() {
-    console.log('writeHtmlOutput', stats.countAllTasks)
+  console.log('writeHtmlOutput', stats.countAllTasks);
 
-    let daysListRef = Object.keys(stats.tasksByDay).sort()
-    let filterInfo = ``
-    if (enableFilterByTag) {
-        filterInfo = `<p class="is-info">Contenu filtré sur le tag: ${filterByTag}. ${countExcluded} tâches exclues, ${countIncluded} tâches inclues sur le total de ${countExcluded + countIncluded}</p>`
-    }
+  let daysListRef = Object.keys(stats.tasksByDay).sort();
+  let filterInfo = ``;
+  if (enableFilterByTag) {
+    filterInfo = `<p class='is-info'>Contenu filtré sur le tag: ${filterByTag}. ${countExcluded} tâches exclues, ${countIncluded} tâches inclues sur le total de ${countExcluded + countIncluded}</p>`;
+  }
 
-    let htmlOut = `
+  let htmlOut = `
     <html>
     <head>
         <title>
         Rapport d'activité
         </title>
-        <meta charset="UTF-8" />
+        <meta charset='UTF-8' />
          <style>
             @import "https://cdn.jsdelivr.net/npm/bulma@0.9.4/css/bulma.min.css";
         </style>
     </head>
     <body>
 
-    <div id="report_days" class="container content">
-        <h1 class="title is-1">Feuille de rapport d'activité</h1>
-    <p class="subtitle is-1">par <a href="https://www.cipherbliss.com">Tykayn</a> </p>
+    <div id='report_days' class='container content'>
+        <h1 class='title is-1'>Feuille de rapport d'activité</h1>
+    <p class='subtitle is-1'>par <a href='https://www.cipherbliss.com'>Tykayn</a> </p>
     ${filterInfo}
+    ${RenderStatsMonth()}
     
-    `
-    daysListRef.reverse().forEach((dayRefString) => {
+    `;
+  daysListRef.reverse().forEach((dayRefString) => {
 
-        let tasksOfTheDay = '';
+    let tasksOfTheDay = '';
 
-        stats.tasksByDay[dayRefString].forEach((dayObj) => {
-            let graphicKeyword = '✅'
-            if ('DONE' !== dayObj.todoKeyword) {
-                graphicKeyword = dayObj.todoKeyword;
-            }
+    stats.tasksByDay[dayRefString].forEach((dayObj) => {
+      let graphicKeyword = '✅';
+      if ('DONE' !== dayObj.todoKeyword) {
+        graphicKeyword = dayObj.todoKeyword;
+      }
 
-            let tagDisplay = '';
-            // console.log('dayObj.tags', dayObj.tags)
-            if (dayObj.tags && dayObj.tags.length ) {
-                tagDisplay = `  <p class="archived-tags tag is-light is-primary">
+      let tagDisplay = '';
+      // console.log('dayObj.tags', dayObj.tags)
+      if (dayObj.tags && dayObj.tags.length) {
+        tagDisplay = `  <p class='archived-tags tag is-light is-primary'>
                   ${dayObj.tags}
                 </p>
-                `
-            }
+                `;
+      }
 
-            tasksOfTheDay += ` <li>
+      tasksOfTheDay += ` <li>
  <h2> 
- <span class="keyword"> ${graphicKeyword}</span>
- <span class="title"> ${dayObj.title} </span>
+ <span class='keyword'> ${graphicKeyword}</span>
+ <span class='title'> ${dayObj.title} </span>
  </h2>
  ${tagDisplay}
- </li>`
-        })
-        htmlOut += `
-<div class="box">
+ </li>`;
+    });
+    htmlOut += `
+<div class='box'>
 
-        <h1 class="title is-1">
-            <span class="day-ref">
+        <h1 class='title is-1'>
+            <span class='day-ref'>
                 ${dayRefString}
             </span>
-            <span class="counter pull-right tag is-success is-light">
+            <span class='counter pull-right tag is-success is-light'>
                 ${stats.tasksByDay[dayRefString].length}
             </span>
         </h1>
         
-        <div class="day-detail">
+        <div class='day-detail'>
             <ul>
                 ${tasksOfTheDay}        
             </ul>
         </div>
       
-</div>  `
-    })
-    htmlOut += ` 
- <div class="box">
- <h1 class="title is-1">
+</div>  `;
+  });
+  htmlOut += ` 
+ <div class='box'>
+ <h1 class='title is-1'>
  
 Tadam, c'est tout!
 </h1>
 <p>
 
-Source: <a href="https://forge.chapril.org/tykayn/org-report-stats">org-report-stats</a>
+Source: <a href='https://forge.chapril.org/tykayn/org-report-stats'>org-report-stats</a>
 <br>
-Contactez-moi: <a href="https://www.cipherbliss.com/contact">par un de ces moyens</a>
+Contactez-moi: <a href='https://www.cipherbliss.com/contact'>par un de ces moyens</a>
 </p>
 </div>
 </div>
 
 </body>
 </html>
-    `
+    `;
 
-    fs.writeFile('output/output.json', JSON.stringify(stats), function (err, data) {
-        if (err) {
-            return console.log(err);
-        }
-        console.log('wrote output json', data)
-    })
-    fs.writeFile('output/output_' + outputFileName + '.html', htmlOut, function (err, data) {
-        if (err) {
-            return console.log(err);
-        }
-        console.log('wrote output html ' + outputFileName, data)
-
-    })
-    if (enableFilterByTag) {
-        console.log('excluded tasks by tag filter ', countExcluded)
+  fs.writeFile('output/output.json', JSON.stringify(stats), function (err, data) {
+    if (err) {
+      return console.log(err);
     }
-}
+    console.log('wrote output json', data);
+  });
+  fs.writeFile('output/output_' + outputFileName + '.html', htmlOut, function (err, data) {
+    if (err) {
+      return console.log(err);
+    }
+    console.log('wrote output html ' + outputFileName, data);
 
+  });
+  if (enableFilterByTag) {
+    console.log('excluded tasks by tag filter ', countExcluded);
+  }
+}
 
 function sortObj(obj) {
-    return Object.keys(obj).sort().reduce(function (result, key) {
-        result[key] = obj[key];
-        return result;
-    }, {});
+  return Object.keys(obj).sort().reduce(function (result, key) {
+    result[key] = obj[key];
+    return result;
+  }, {});
 }