*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19729
19732
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19851
19866
19872
19881
198910
199014
199111
19920
19934
19946
19950
19961
19970
19980
19990
20002
20013
20021
20030
20040
200517
20061
20071
20081
20091
20102
20110
20120
20131
20140
20150
20160
20170
20180
20190
Total97