*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970001001
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977002002
1978000000
1979005005
1980002002
1981002002
1982002002
1983000000
1984000000
1985003003
1986006006
1987008008
1988009009
198900100010
199000140014
199100190019
199200160016
199300200020
199400160016
199500350035
199600180018
199700220022
199800260026
199900140014
200000310031
200100460046
200200700070
200300340034
200400170017
200500180018
200600190019
200700340034
200800240024
200900480048
201000290029
201100510051
201200170017
201300160016
2014002002
2015004004
2016000000
2017000000
Total0071000710