*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977001001
1978000000
1979000000
1980002002
1981001001
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000000
1990001001
1991001001
1992001001
1993000000
1994001001
1995001001
1996001001
1997001001
1998000000
1999000000
2000001001
2001001001
2002002002
2003000000
2004000000
2005000000
2006001001
2007000000
2008001001
2009001001
2010000000
2011000000
2012002002
2013002002
2014000000
2015000000
2016000000
2017000000
Total00220022