*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
2003640
200428
200560
20063
20071
20084
200961
20104
20111
20120
20130
20140
20152
20168
20170
20180
Total863