*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19863
19870
19880
19890
19900
19910
19920
19930
19941
19956
19961
199712
19988
199912
20000
20011
20026
20030
20044
200512
20060
20070
20080
20090
20103
20111
20120
20130
20140
20151
20166
20170
Total78