*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19773
19782
19790
19800
19810
19821
19830
19840
19850
19861
19871
19880
19891
19901
19911
19920
19930
19940
19950
19960
19970
19981
19992
20004
20011
20020
20030
20040
20050
20060
20073
20080
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total22