*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19786
19790
19801
19810
19820
19830
19841
198517
19864
19872
198816
19892
19901
19912
199213
199311
19944
199511
19961
19972
19981
19990
20003
20010
20021
20037
20045
20051
20062
20077
20088
20095
20101
20117
20126
20137
20145
20158
20162
20173
20180
20192
20200
20210
20220
Total175