*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19841
19850
198613
19870
19882
19890
19900
19916
19926
19938
19948
19954
19969
19977
19980
19990
20000
20012
20020
20030
20040
20057
20061
20072
20080
20091
20104
20112
20121
20131
20141
20150
20160
20171
20180
Total87