*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000404
1970000000
1971000101
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000101
1982000000
1983000000
1984000101
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000101
1992000000
1993000000
1994000000
1995000000
1996000000
1997000000
1998000202
1999000000
2000000000
2001000000
2002000202
2003000000
2004000202
2005000101
2006000000
2007000101
2008000303
2009000101
2010000303
2011000000
2012000000
2013000000
2014000000
2015000000
2016000000
2017000000
2018000000
Total00023023