Pivot Table creating numerous columns instead of summing data correctly

In the attached workbook, my Pivot Tables are working fine for summing up the data in columns by Month but it is not summing it up correctly by Year. There is only three years of data - 2012, 2013, and 2014. Instead of aggregating the data by year into three columns, it creates a new column for every entry - i.e. creating over 900 columns! Why is that and how do I fix it? See file named Excel Forum Help. Thanks.