*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19850
19860
19871
19881
19890
19900
19911
19920
19930
19940
19953
19960
19970
19980
19990
20000
20011
20020
20030
20040
20050
20060
20070
20080
20090
201012
20111
20121
20130
20141
20150
20160
20171
20180
20190
Total24