*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 197026000026
1970200002
1971500005
1972200002
1973300003
1974300003
1975400004
1976300003
1977500005
1978800008
1979600006
1980700007
1981500005
1982500005
1983500005
1984600006
1985300003
1986800008
1987700007
19889001010
198911000011
1990800008
1991500308
1992500005
199310000010
1994700108
199510003013
199610005015
199713004017
199890014023
199911001012
200010005015
200110002012
20029108018
20039103013
2004900009
200515003018
20067006114
200712205120
20087004112
2009300317
2010200428
201121011014
20125106012
2013100719
2014010427
2015000606
2016100001
2017000000
2018000000
Total323701099448