*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19840
19850
19860
19870
19880
19897
19901
19910
19920
19930
19944
19950
19963
19970
19980
19991
20001
20010
20020
20030
20040
20050
20060
20070
20080
20090
20100
20110
20121
20130
20140
20151
20161
20172
20180
Total23