*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000101
1975000000
1976000000
1977000202
1978000101
1979000101
1980000606
1981000202
1982000000
1983000101
1984000101
1985000000
1986000000
1987000101
1988000202
1989000000
1990000101
1991000000
1992000505
1993000202
1994000101
1995000000
1996000303
1997000000
1998000101
1999000000
2000000000
2001000202
2002000000
2003000101
2004000404
2005000000
2006000202
2007000000
2008000101
2009000000
2010000202
2011000505
2012000000
2013000000
2014000000
2015000000
2016000000
2017000000
2018000000
Total00048048