*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19850
19860
19870
19882
19890
19900
19910
19920
19930
19940
19951
19960
19970
19980
19992
20000
20010
20023
20031
200434
20050
20061
20070
200811
20090
20101
20112
20120
20130
20140
20150
20160
20170
Total59