*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988000000
1989000202
1990000101
1991000202
1992000000
1993000202
1994000303
1995000202
1996000202
1997000202
1998000101
1999000000
2000000000
2001000000
2002000505
2003000808
2004000101
2005000303
2006000404
2007000303
2008000404
2009000303
2010000707
201100012012
2012000202
2013000202
2014000202
2015000000
2016000000
2017000000
2018000000
Total00073073