*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000101
1970000000
1971000000
1972000101
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000101
1981000000
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000000
1992000000
1993000000
1994000202
1995000101
1996000000
1997000000
1998000202
1999100001
2000000101
2001000101
2002000000
2003000101
2004000000
2005000000
2006000303
2007000101
2008000303
2009000303
2010000000
2011000000
2012000000
2013000000
2014000101
2015000000
2016000000
2017000000
2018000000
Total10022023