*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977001001
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000011
1992002024
1993001001
1994000011
1995004105
1996003003
1997001001
1998001001
1999002024
2000001012
2001002002
2002002013
2003003003
2004001001
2005003003
2006002013
2007001023
2008000000
2009002002
2010002002
2011002002
2012000000
2013000011
2014000000
2015000000
2016000000
2017000000
Total003611249