*Excludes Observations that span multiple months

  B
b
t
W
w
 
Jan0004301305
Feb20137077216
Mar681433001447
Apr3212313002337
May101602113002283
Jun491851925002159
Jul631438900466
Aug16224800266
Sep1048600487
Oct0062800628
Nov0035600356
Dec00790446525
Total15039010107482411475