*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
19860
19870
198816
19891
19900
199128
19927
19936
19942
19950
19960
19971
19980
19991
20000
20010
20020
20030
20041
20051
20060
20072
20086
20090
20104
20114
20120
20130
20140
20150
20160
20170
Total81