*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19821
19832
19840
19851
19863
19871
19880
19892
19900
19910
19920
19933
19941
19951
19960
19972
19980
19990
20000
20011
20020
20034
20040
20050
20061
20070
20081
20090
201066
201159
20120
20130
20140
20150
20160
20170
Total150