*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 19701080010109
1970400004
1971900009
1972700108
1973800008
1974600107
1975900009
197614002016
197714002016
197811003014
197915003018
198018002020
198117003020
198219003022
198315001016
198421000021
198517103021
198622006331
1987240012137
198823005129
198920019434
199020117837
1991170218845
1992220210741
19932524231165
199428045318103
1995263240778
19962011401072
1997310134874
19982502332181
19992501121149
20003803401091
2001320127868
20021821541186
200328358321140
2004291012518173
200534115533124
200632257526140
200737238522149
2008277213814188
2009201110129152
2010282113232195
2011370019334264
201243108528157
20134209315114
2014111362160
201500026329
2016000909
2017000202
2018000000
Total1048334516864433255