*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19850
19860
19875
19889
19892
19901
199111
19923
199311
19947
19950
19961
19970
19980
19990
20000
20012
20022
20031
20040
20051
20060
20070
20089
20090
20109
201110
20120
20130
20140
20150
20160
20170
Total85