*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000202
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000101
1978000000
1979000000
1980000000
1981000000
1982000101
1983000000
1984000101
1985000101
1986000000
1987000101
1988000303
1989000303
1990000505
1991000707
1992000303
1993000606
1994000606
199500012012
1996000404
1997000606
199800012012
1999000404
200000018018
200100019019
200200018018
200300019019
2004000606
200500011011
2006000303
2007000808
2008000707
200900010010
2010000606
2011000707
2012000606
2013000202
2014000000
2015000202
2016000000
2017000000
2018000000
Total0002200220