*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000101
1970000000
1971000000
1972000000
1973000000
1974000101
1975000101
1976000000
1977000000
1978100001
1979100001
1980100001
1981000000
1982100001
1983100001
1984100001
1985000000
1986000000
1987000000
1988100102
1989100102
1990100001
1991100001
1992100001
1993100001
1994200002
1995300003
1996100102
1997400206
1998300003
1999200103
2000200709
2001600309
2002010203
2003100001
2004100203
2005000202
2006400206
2007200002
2008100405
2009300407
2010000000
20114008012
2012200103
2013000000
2014000000
2015000000
2016000000
2017000000
2018000000
Total531044098