*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19802
19810
19820
19830
19841
198524
19860
19871
19880
19891
19905
199137
199276
19934
19947
19956
19961
199726
19981
19990
20000
200118
20021
200318
20044
20050
20061
20071
20080
20090
201022
201124
20123
201328
20149
20155
201622
201742
201842
201958
20200
Total491