*Excludes Observations that spanned multiple years

Pre 19701
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19903
19910
19920
19931
19947
19950
19960
19970
19980
19990
20000
20010
20020
20031
20040
20051
20060
20070
20083
20090
20102
20118
20120
20130
20140
20150
20160
20170
Total27