*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977002002
1978000000
1979001001
1980000000
1981000000
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000000
1992000000
1993000000
1994001001
1995000011
1996000000
1997000000
1998000000
1999000000
2000001001
2001000000
2002000000
2003000000
2004002002
2005003003
2006002002
2007001001
2008001001
2009000000
2010000000
2011001001
2012002002
2013001001
2014001001
2015002002
2016001001
2017000000
Total00220123