*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19881
19892
19905
19912
19920
19932
19940
19950
19961
19970
19980
19990
20000
20010
20020
20039
20040
20050
20060
20070
20081
20090
20100
20111
20120
20130
20142
20150
20160
20170
20180
Total26