diff --git a/lib/date_format.js b/lib/date_format.js
index bf36318..d75ce20 100644
--- a/lib/date_format.js
+++ b/lib/date_format.js
@@ -45,7 +45,7 @@ exports.asString = function(/*format,*/ date) {
   var vDay = addZero(date.getDate());
   var vMonth = addZero(date.getMonth()+1);
   var vYearLong = addZero(date.getFullYear());
-  var vYearShort = addZero(date.getFullYear().toString().substring(3,4));
+  var vYearShort = addZero(date.getFullYear().toString().substring(2,4));
   var vYear = (format.indexOf("yyyy") > -1 ? vYearLong : vYearShort);
   var vHour  = addZero(date.getHours());
   var vMinute = addZero(date.getMinutes());