*Excludes Observations that spanned multiple years

Pre 197010
19700
19711
19721
19730
19740
19750
19762
19770
19781
19790
19800
19810
19821
19830
19840
19850
19861
19870
19881
19891
19900
19910
19920
19930
19941
19951
19960
19971
19981
19990
20000
20011
20020
20030
20040
20050
20060
20070
20081
20090
20100
20110
20120
20130
20140
20150
20160
20170
20180
Total25