*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19842
19852
19860
19870
19882
19894
19902
19910
19923
19934
19946
19953
19968
199710
19980
19993
20001
20010
20022
20030
20040
200519
20062
20071
20080
20090
20100
20110
20120
20130
20140
20151
20160
20170
Total75