*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977001001
1978000000
1979000000
1980000000
1981001001
1982000000
1983001001
1984000000
1985000000
1986000000
1987000000
1988000000
1989001001
1990001001
1991000000
1992000000
1993002002
1994002002
1995000000
1996001001
1997000000
1998002002
1999000000
2000001001
2001002002
2002001001
2003000000
2004003003
2005003003
2006001001
2007002002
2008001001
2009001001
2010001001
2011001001
2012000000
2013000000
2014000000
2015000000
2016000000
2017000000
Total00290029