*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970001001
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000011
1979000000
1980000000
1981000000
1982000000
1983000000
1984000000
1985001001
1986000000
1987004004
1988005005
1989000000
1990003003
1991007007
1992008008
199300110011
1994006006
199500100010
1996007007
1997007007
1998006006
1999004004
200000110011
2001008008
2002006006
2003006006
2004003003
2005004004
2006002002
2007006006
2008005005
2009006006
201000140014
201100130114
2012007007
2013008008
2014000000
2015000000
2016000000
2017000000
Total0017902181