*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000404
1970000000
1971000000
1972000101
1973000000
1974000202
1975000101
1976000000
1977000000
1978000000
1979000000
1980000101
1981000101
1982000000
1983000000
1984000000
1985000101
1986000000
1987000000
1988000000
1989000000
1990000101
1991000000
1992000101
1993000000
1994000101
1995000101
1996000303
1997000303
1998000404
1999000202
2000000505
200100013013
2002000303
2003000808
2004000101
2005000000
2006000202
2007000202
2008000202
2009000202
2010000404
2011000101
2012000000
2013000000
2014000000
2015000000
2016000000
2017000000
2018000000
Total00070070