*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
19871
198810
19892
19900
19912
19921
19931
19941
19951
19961
19970
19980
19996
20000
20010
20021
20030
20040
20051
20060
20071
20085
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total34