*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
19903
19910
19927
19931
19940
19950
19960
19970
19980
19990
20002
20010
20020
20030
20040
20050
20060
20070
20082
20090
20108
20117
20120
20130
20140
20150
20162
20170
Total32