*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19871
198811
19890
19901
19913
19921
19930
19941
19950
19960
19974
19980
19990
20001
20010
20020
20032
20041
20051
20060
20070
20085
20090
20104
20112
20122
20132
20142
20152
20164
20172
20180
Total53