*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19851
19860
19870
19880
19890
19900
19910
19920
19932
19940
19951
19960
19970
19981
19990
20001
20010
20020
20030
20040
20050
20060
20070
20081
20090
201022
201111
20120
20130
20140
20150
20160
20170
Total40