*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19841
19852
19860
19870
19880
19896
19904
19911
19922
19933
19941
19950
19960
19973
19980
19991
20004
20012
20021
20030
20041
20050
20061
20070
20083
20090
20102
20113
20121
20130
20141
20151
20166
20172
20180
Total53