*Excludes Observations that spanned multiple years

Pre 19706
19701
19710
19720
19731
19740
19750
19760
19770
19781
19790
19800
19810
19820
19831
19840
19851
19860
19870
19880
19890
19900
19910
19920
19930
19940
19951
19960
19970
19980
19990
20000
20010
20020
20030
20040
20050
20061
20070
20080
20090
20100
20111
20121
20130
20140
20151
20160
20170
Total16