*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000101
1973000000
1974000000
1975000000
1976000101
1977000101
1978000000
1979000000
1980000000
1981000000
1982000101
1983000000
1984000000
1985000000
1986000000
1987000101
1988000000
1989000000
1990000101
1991000101
1992000000
1993000101
1994000101
1995000000
1996000101
1997000202
1998000303
1999000202
2000000202
2001000303
2002000101
2003000000
2004000101
2005000101
2006000000
2007000303
2008000000
2009000000
2010000404
2011000202
2012000000
2013000000
2014000000
2015000101
2016000000
2017000011
2018000000
Total00035136