*Excludes Observations that spanned multiple years

Pre 197012
19700
19710
19720
19730
19741
19750
19760
19771
19780
19790
19800
19810
19820
19830
19840
19850
19862
19873
19881
19890
19900
19910
19920
19930
19942
19950
19960
19971
19980
19990
20000
20010
20020
20030
20040
20050
20061
20070
20080
20090
20105
20111
20120
20131
20140
20150
20160
20170
Total31