*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19841
19851
19862
19870
19880
19890
19900
19910
19928
19930
19941
199523
19960
19970
19981
19990
20000
20012
20021
20030
200431
20050
20061
20070
200815
20090
201020
201110
20120
20132
20141
20150
20160
20170
Total121