*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
198610
19870
19889
19890
19900
19910
19921
19936
19945
19956
19965
19979
19980
19993
20001
20013
20020
20031
20040
20057
20060
20070
20082
20090
20108
20114
20120
20130
20140
20150
20162
20170
Total82