*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 197000002626
1970000022
1971000055
1972000022
1973000033
1974000033
1975000044
1976000033
1977000055
1978000088
1979000066
1980000077
1981000055
1982000055
1983000055
1984000066
1985000033
1986000088
1987000077
19880010910
198900001111
1990000088
1991003058
1992000055
199300001010
1994001078
199500301013
199600501015
199700401317
199800140923
199900101112
200000501015
200100201012
20020081918
20030031913
2004000099
200500301518
20060160714
200701521220
20080140712
2009013037
2010024028
201100111214
20120061512
2013017019
2014024107
2015006006
2016000011
2017000000
Total091097323448