*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000606
1970000505
1971000000
1972000404
1973000000
1974000000
1975000101
1976000101
1977000101
1978000202
1979000101
1980000202
1981000101
1982000000
1983000000
1984000000
1985000000
1986000101
1987000101
1988000000
1989000101
1990000000
1991000101
1992000404
1993000000
1994000303
1995000303
1996000404
1997000404
1998100203
1999000000
2000000000
2001000606
2002000404
2003000000
2004000303
2005100607
2006000404
2007000505
2008000101
2009000505
2010000101
2011000909
2012000404
2013000101
2014000000
2015000000
2016000202
2017000101
2018000000
Total2001000102