*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
19887
19890
19900
19910
19920
19932
19941
19951
19962
19970
19982
19996
20000
20011
20021
20031
20040
20051
20062
20071
20084
20091
20102
20113
20120
20130
20140
20150
20161
20170
Total39