The results for the months look fine.

The query returns

28November2012-11

40December2012-12

84January2013-01

64February2013-02

73March2013-03

119April2013-04

99May2013-05

70June2013-06

95July2013-07

113August2013-08

100September2013-09

187October2013-10

65November2013-11

NULLNULLNULL