*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000000
1992000000
1993000000
1994000000
1995000000
1996000000
1997000000
1998001001
1999001001
2000001001
2001001001
2002001001
2003000000
2004001001
2005003003
2006003003
2007005005
2008001001
2009001001
2010002002
2011001001
2012000000
2013000000
2014001001
2015000000
2016000000
2017000000
Total00230023