*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19721
19731
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19865
198733
19887
19891
19908
19918
19924
19932
19940
19950
19961
19970
19980
199912
20006
20010
20022
20030
20040
20050
20060
20070
20080
20090
20100
20110
20120
20131
20141
20151
20163
20170
20180
20190
Total97