*Excludes Observations that spanned multiple years

Pre 19701
19700
19710
19720
19730
19740
19756
19763
19770
19780
19790
19801
19810
19820
19830
19841
19852
19860
19871
19881
19891
199011
199155
199242
199323
19949
199515
199615
199712
199810
19990
20000
20019
20022
20030
20040
20050
20060
20071
20080
20092
20100
20110
20120
20130
20140
20150
20161
20170
Total224