*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
19897
19902
19912
19921
19939
19948
199543
19962
199711
199815
19997
200012
20011
20028
20030
20044
20050
20061
20070
20080
20090
20100
20110
20120
20130
20142
20150
20161
20170
Total136