diff --git a/app.js b/app.js
index ad9a93a7..3ef78432 100644
--- a/app.js
+++ b/app.js
@@ -1 +1,54 @@
 'use strict';
+const fs = require('fs');
+const readline = require('readline');
+const rs = fs.ReadStream('./popu-pref.csv');
+const rl = readline.createInterface({ 'input': rs, 'output': {}
+});
+const map = new Map(); // key: 都道府県 value: 集計データのオブジェクト
+rl.on('line', (lineString) => {
+    const columns = lineString.split(',');
+    const year = parseInt(columns[0]);
+    const prefecture =columns[2];
+    const popu = parseInt(columns[7]);
+    if(year === 2010 || year === 2015){
+        let value = map.get(prefecture);
+        if(!value){
+            value = {
+                popu10: 0,
+                popu15: 0,
+                change: null
+            };
+        }
+        if(year === 2010){
+            value.popu10 += popu;
+        }
+        if(year === 2015){
+            value.popu15 += popu;
+        }
+        map.set(prefecture, value);
+        // console.log(year);
+        // console.log(prefecture);
+        // console.log(popu);
+    }
+//    console.log(lineString);
+});
+rl.resume();
+rl.on('close', () => {
+    for (let pair of map){
+        const value = pair[1];
+        value.change = value.popu15 / value.popu10;
+    }
+    // const rankingArray = Array.from(map).sort((pair1,pair2) => {
+    //     return pair2[1].change -pair1[1].change;
+    // });
+    const rankingArray = Array.from(map).sort((pair1,pair2) => {
+        return pair1[1].change -pair2[1].change;
+    });
+    const rankingStrings = rankingArray.map((pair, i) => {
+        return i+1 + "位: "+ pair[0] + ': ' + pair[1].popu10 + '=>' + pair[1].popu15 + ' 変化率:' + pair[1].change;
+    });
+    console.log('2010年から2015年にかけて15～19歳の人が減った割合の都道府県ランキング');
+    console.log(rankingStrings);
+//    console.log(rankingArray);
+//    console.log(map);
+});
\ No newline at end of file