*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
19900
19910
19922
19930
19941
19950
19960
19973
19980
19990
20000
20012
20021
20030
200426
20052
20061
20070
20080
20096
20102
20116
20120
20133
20140
20150
20160
20170
20180
Total55