*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19852
19865
19872
198810
198916
199012
199126
19927
19930
19940
19950
19960
19970
19980
19993
20002
20014
20020
20030
20040
20050
20061
20071
20084
20091
201010
20116
20120
20130
20141
20158
201617
20175
20182
20190
Total146