*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000404
1970000101
1971000202
1972000303
1973000101
1974000101
1975000101
1976000000
1977000101
1978000000
1979000000
1980000000
1981000000
1982000101
1983000000
1984000000
1985000000
1986000000
1987000000
1988000101
1989000000
1990000000
1991000202
1992000303
1993000000
1994000303
1995000202
1996000000
1997000202
1998000404
1999000303
2000000202
2001000404
2002000202
2003000101
2004000000
2005000303
2006000000
2007000000
2008000000
2009000101
2010000000
2011000000
2012000000
2013000000
2014000000
2015000000
2016000000
2017000000
2018000000
Total00048048