*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19874
19880
19892
19900
19910
19920
19931
19941
199537
19960
19971
199815
19993
200013
20010
20020
20030
20045
20050
20061
20070
20081
20090
20100
20110
20120
20131
20140
20150
20160
20170
Total85