*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970100001
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978100001
1979000000
1980000000
1981000000
1982100001
1983000000
1984300003
1985200103
1986100001
1987310004
1988210104
1989100001
1990400105
199130011014
199250012017
1993400408
1994400307
19956004010
19963008011
19978004012
1998400307
1999400206
2000400105
2001500308
20024007011
2003200709
20048004012
20058003011
2006500207
20076103010
20088003011
2009100102
2010300104
20113106010
2012600309
2013000101
2014000000
2015000101
2016100001
2017000101
2018000000
Total124401010229