*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19870
19880
19890
19900
19913
19922
19930
19940
19950
19960
19975
19980
19991
20000
20010
20020
20031
20046
20050
20061
20070
20080
20090
20100
20111
20120
20131
20140
20151
20163
20170
20181
20190
Total27