*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197277
197331
19740
19750
19760
19770
19780
19790
19801
19810
19820
19834
19840
198533
198610
1987138
1988214
198979
1990287
1991370
1992243
1993142
19946
19955
19963
199712
199815
199993
200068
200160
20029
200313
200456
20056
20064
200720
200817
200912
20108
201111
201215
201323
201416
20158
201645
201749
20180
Total2203