*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000101
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000101
1977000000
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000101
1985000000
1986000000
1987000000
1988000000
1989000101
1990000000
1991000000
1992000000
1993000202
1994100001
1995000202
1996100102
1997000101
1998000202
1999000202
2000000000
2001000404
2002000202
2003000606
2004100304
2005000101
2006000000
2007000303
2008000202
2009000202
2010000000
2011000101
2012000202
2013000000
2014000000
2015000000
2016000000
2017000000
2018000000
Total30040043