diff --git a/app.js b/app.js
index ad9a93a7..346d6c20 100644
--- a/app.js
+++ b/app.js
@@ -1 +1,50 @@
 'use strict';
+const fs = require('fs');
+const readline = require('readline');
+const rs =fs.createReadStream('./popu-pref.csv');
+const rl = readline.createInterface({input: rs, output: {} });
+const prefectureDateMap = 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[1];
+    const popu = parseInt(columns[3]);
+    if(year === 2010 || year === 2015){
+        let value = prefectureDateMap.get(prefecture);
+        if(!value){
+            value = {
+                popu10: 0,
+                popu15: 0,
+                change: null
+            };
+        }
+        if(year === 2010){
+            value.popu10 = popu;
+        }
+        if(year === 2015){
+            value.popu15 = popu;
+        }
+        prefectureDateMap.set(prefecture, value);
+    }
+});
+rl.on('close', () => {
+    for(let [key, value] of prefectureDateMap){
+        value.change = value.popu15 / value.popu10;
+    }
+    const rankingArray = Array.from(prefectureDateMap).sort((pair1, pair2) =>{
+        return pair1[1].change - pair2[1].change;
+    });
+    const rankingStrings = rankingArray.map(([key, value], i) => {
+        i = i + 1;
+        return(
+            i + '位' +
+            key + ': ' +
+            value.popu10 + '=>' +
+            value.popu15 + ' 変化率:' +
+            value.change
+        );
+    });
+    console.log(rankingStrings);
+});
+
+