*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000101
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000101
1983000000
1984000202
1985000000
1986000134
1987000224
1988000202
1989000268
1990000145
1991002417
1992000167
199300032831
1994000107080
199500001515
199600132832
199700024951
199800113840
199900001515
200000065258
200100111012
200200245965
200300033538
200400036972
200500021618
200600033336
2007000112738
2008002115770
2009001231337
2010001141732
201100121729
201200221822
2013000181836
2014000101626
2015000336
2016000112
2017000000
2018000000
Total0014172716902