*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19852
19860
19871
19882
19890
19902
199129
19924
19934
19941
199521
19960
19971
19981
19990
20000
20011
20020
20030
20043
20051
20060
20070
20080
20090
20100
20110
20120
20130
20140
20150
20161
201710
20180
20190
20201
Total85