*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19727
19731
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19851
19860
19870
19881
19891
19900
19911
19920
19939
19940
19954
19964
19976
19981
19994
20002
20010
20020
20030
20040
20050
20060
20070
20085
20091
20100
20110
20120
20130
20140
20150
20162
20173
20180
20190
20200
Total54