*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19761
19770
19780
19790
19802
19810
19820
19834
19841
19850
19860
19870
19880
19890
19901
199118
19920
19930
19940
19951
19960
19970
199810
19996
20000
20010
20020
20030
20040
20051
20060
20070
20081
20099
20100
20113
20122
20130
20140
20150
20160
20170
20180
Total60