*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19822
19830
19840
19850
19863
19874
19880
19893
19902
19910
19920
19934
19947
19951
19960
19972
19980
19990
20000
20011
20020
20030
20042
200512
20063
20070
20084
20090
201043
201170
20120
20137
20147
20150
20160
20170
Total177