diff --git a/app.js b/app.js
index ad9a93a7..f8230f88 100644
--- a/app.js
+++ b/app.js
@@ -1 +1,57 @@
 '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();
+
+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 = { popu2010: 0, popu2015: 0, change: null };
+		}
+		if (year === 2010)
+		{
+			value.popu2010 += popu;
+		}
+		if (year === 2015)
+		{
+			value.popu2015 += popu;
+		}
+		map.set(prefecture, value);
+	}
+});
+
+rl.resume();
+
+rl.on('close', () =>
+{
+	for(let pair of map)
+	{
+		const value = pair[1];
+		value.change = value.popu2015 / value.popu2010;
+	}
+	
+	const rankingArray = Array.from(map);
+	rankingArray.sort((pair1, pair2) =>
+	{
+		return pair1[1].change - pair2[1].change;
+	});
+	
+	const rankingStrings = rankingArray.map((pair) =>
+	{ 
+		return pair[0] + ':' + pair[1].popu2010 + '=>' + pair[1].popu2015 + ' 変化率:' + pair[1].change;
+	});	
+	console.log(rankingStrings);
+});