*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19870
19880
19892
19905
19912
19922
19935
19942
19950
19964
19974
19981
19990
20001
20010
20023
20030
20040
20051
20060
20070
20084
20090
20100
20110
20120
20130
20140
20150
20162
20170
Total39