*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197220
197312
19740
19750
19760
19770
19780
19790
19800
19810
19820
19832
19840
198529
198610
198750
198892
198931
1990129
1991233
1992196
199332
19942
19950
19965
19979
19980
19990
20004
200111
20020
20039
20041
20051
20060
20070
20082
20090
20100
20110
20120
20130
20140
20150
20160
20171
20180
Total881