*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970001001
1970000000
1971000000
1972000000
1973000000
1974000000
1975001001
1976000000
1977001001
1978000000
1979000000
1980000000
1981002002
1982000000
1983000000
1984000000
1985000000
1986003003
1987008008
1988004004
1989001001
1990004004
1991007007
1992006006
1993004004
199400110011
199500180018
199600140014
199700120012
1998006006
199900100010
200000190019
200100180018
200200210021
200300270027
2004009009
200500510051
2006007007
200700220022
200800130013
200900670067
201000380038
201100240024
201200410041
201300100010
2014000000
2015004004
2016000000
2017000000
Total0048400484