*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19800
19810
19821
19830
19843
19850
19860
19870
19881
198923
19905
19910
19924
19930
19940
19950
19960
19972
19980
19991
20000
20011
20020
20031
20040
20053
20064
20071
20080
20090
20100
20111
20120
20130
20140
20150
20160
20170
Total52