*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 197000120012
1970000000
1971002002
1972002002
1973000000
1974000000
1975000000
1976001001
1977004004
1978000000
1979106007
1980107008
1981107008
1982107008
1983202004
1984204006
19851270010
1986303006
19874150010
19885150011
1989112004
1990213006
1991125008
1992024006
19932080010
199422100014
199522130017
199642150021
19972090011
199830120015
1999115007
20005050010
20013180012
2002007007
200302130015
200420110013
200520160018
2006203005
200730140017
200820130015
2009120280040
2010100260036
201191370047
2012008008
2013008008
2014000000
2015000000
2016002002
2017000000
Total912135900471