*Excludes Observations that spanned multiple years

Pre 19700
19700
19711
197229
197317
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19840
198519
19860
198737
1988142
198929
1990152
1991266
199279
199367
199410
199511
19960
199716
19981
19992
20002
20012
20024
20031
20044
200516
20060
20073
20080
20090
20101
20111
20126
20136
20141
20152
20162
201710
20180
Total940