*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970001001
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977001001
1978000000
1979001001
1980000000
1981002002
1982001001
1983000000
1984000000
1985002002
1986003003
1987002002
1988004004
1989005005
1990007007
199100130013
1992007007
1993006006
199400110011
199500200020
199600150015
199700110011
199800150015
1999009009
200000480048
200100350035
200200430043
200300160016
200400120012
2005007007
200600170017
200700240024
2008009009
200900290029
201000190019
201100430043
201200300030
2013007007
2014001001
2015006006
2016000000
2017000000
Total0048200482