*Excludes Observations that span multiple months

  B
b
t
W
w
 
Jan00005858
Feb035403087
Mar03610400140
Apr031657600892
May299529800422
Jun1573344000630
Jul1111727900407
Aug28727000305
Sep8214900159
Oct1011600117
Nov00950095
Dec002914272
Total334509241011303384