*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19871
19881
19890
19900
19910
19920
19930
19942
19953
19965
19970
19980
19990
20001
20010
20020
20030
20040
20054
20060
20070
20080
20090
20101
20112
20120
20131
201411
20150
20160
20170
Total33