*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19732
19740
19750
19760
19770
19781
19790
19801
19810
19820
19830
19842
19850
19860
19870
19881
19890
19900
19911
19920
19930
19940
19950
19960
19970
19981
19990
20000
20010
20020
20030
20040
20050
20060
20070
20080
20090
20100
201110
201261
201321
20140
201517
201619
20170
20180
20190
Total137