*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
19870
19880
19890
19902
19910
19920
19931
19941
19950
19960
19970
19980
19990
20000
20010
20022
20030
20040
20050
20060
20070
20080
20090
20109
20115
20120
20130
20140
20150
20160
20170
Total20