diff --git a/chapter2/mysite/myapp/static/scripts/trend.js b/chapter2/mysite/myapp/static/scripts/trend.js
index 9a8fb76..012f81b 100755
--- a/chapter2/mysite/myapp/static/scripts/trend.js
+++ b/chapter2/mysite/myapp/static/scripts/trend.js
@@ -229,7 +229,7 @@ $(function(){
     var data = top10_sells[key];
     histogramChart3_names.push(data['product_name']);
     histogramChart3_datas.push(data['good_c']);
-    var rate = base['good_c'] * 100 / data['good_c'];
+    var rate = data['good_c'] * 100 / base['good_c'];
     histogramChart3_rates.push(rate.toFixed(0));
    }