*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 197000109596
1970001045
1971001089
1972001078
19730020810
1974002068
1975000088
197600201113
197700401317
19780020911
197900101516
198000701522
198100301316
198200601521
198300301619
198400201719
198500211215
198600401822
198703701828
1988041102136
1989151801842
199025802035
19918172401564
1992592811659
1993103166123131
1994457170022253
1995647140321217
1996177196016290
199725753024136
1998316141020180
19990242001963
2000419183027233
200163162027198
200223274215296
2003423258220307
200427211024244
2005203166230149
200627173132215
2007629313128377
2008154137122215
200911598017131
2010222210019253
2011270123027222
201207049221142
201303314505183
201401069211200
201512230026
2016062019
2017111104
Total968533446198595273