*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000101
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000000
1992000000
1993000101
1994000000
1995000101
1996000303
1997000303
1998000101
1999000101
2000000101
2001000101
2002000404
2003000303
2004000000
2005000202
2006000303
2007000606
2008000404
2009000404
2010000707
2011000404
2012000202
2013000000
2014000000
2015000000
2016000101
2017000000
2018000000
Total00053053