*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
19881
19890
199013
19910
199224
19932
19940
19951
19961
19972
19980
19990
20000
20010
20025
20030
20040
20050
20060
20070
20080
20090
20103
20112
20120
20130
20140
20150
20160
20170
20180
20190
20200
Total54