*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19771
19780
19790
19800
19810
19821
19830
19840
19850
19860
19870
19880
19891
19900
19915
19921
19933
19940
199531
19960
19970
199818
19993
20001
20012
20024
20033
20044
20059
20061
20073
20081
20090
20100
20110
20120
20130
20140
20153
20166
20170
Total101