*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
19901
19911
19922
19934
19940
19951
19960
19970
19980
19990
20000
20010
20020
20030
20042
20051
20060
20070
20080
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total12