*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19822
19831
19840
19852
19861
19871
198818
19891
199018
199112
19922
199313
19947
19952
199611
199713
19984
19992
20000
20010
20024
200322
20046
20050
20061
20071
20083
20092
20101
20111
20120
20130
20140
20150
20162
20170
Total153