*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19841
19850
19860
19871
19885
19890
19900
19912
19920
19930
19940
19952
19961
19970
19980
19992
20001
20010
20020
20030
20040
20050
20060
20070
20080
20090
20101
20111
20120
20130
20140
20150
20161
20176
20183
20190
20200
Total28