*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970001023
1970000000
1971000000
1972000000
1973000011
1974000000
1975000000
1976000011
1977000011
1978000000
1979000000
1980000000
1981000022
1982000011
1983000000
1984000022
1985000000
1986000011
1987000000
1988000000
1989000011
1990000000
1991003014
1992001023
1993000011
1994001001
1995000000
1996000011
1997000011
1998000022
1999000011
2000000033
2001000099
2002002002
2003001012
2004000011
2005000011
2006001001
2007002035
2008000000
2009000000
2010000000
2011001012
2012001034
2013000000
2014000000
2015000000
2016000000
2017000000
Total001404357