*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970100012
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000101
1978000000
1979100001
1980000000
1981100102
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000101
1989000000
1990000000
1991000011
1992000202
1993000101
1994000000
1995000202
1996100405
1997000202
1998100304
1999100102
2000000202
2001001001
2002000000
2003000011
2004000000
2005000101
200600010111
2007200215
2008100102
2009000000
2010000404
2011000303
2012000303
2013000101
2014000202
2015000202
2016000213
2017000000
2018000000
Total90151667