*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 197000017017
1970000000
1971000000
1972000202
1973000101
1974000303
1975000303
1976000101
1977000000
1978000101
1979000303
1980000000
1981000101
1982000101
1983000101
1984000000
1985000505
1986000000
1987000101
1988000202
1989000101
1990000303
1991000101
1992000101
1993000202
1994000202
1995000101
1996000000
1997000000
1998000404
1999000000
2000000000
2001000000
2002000000
2003000101
2004000000
2005000202
2006000000
2007000000
2008000202
2009000000
2010000101
2011000101
2012000101
2013000000
2014000101
2015000000
2016000000
2017000000
2018000000
Total00066066