*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19722
19731
19747
19750
19766
19771
19780
19790
19800
19811
19821
19830
19840
19850
19860
19872
19880
19891
19900
19910
19921
19930
19940
19950
19960
19970
19980
19990
20000
20010
20020
20030
20040
20050
20060
20070
20080
20090
20101
20110
20120
20130
20141
20150
20160
20170
Total25