*Excludes Observations that spanned multiple years

Pre 19700
19700
19711
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19841
19850
19861
19871
198830
19895
19901
199120
199215
199321
19944
19958
19962
19976
19984
19991
20000
20012
20020
20033
20045
20051
20066
20070
200815
20090
201012
201111
20120
20130
20140
20150
20161
20170
Total178