*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19821
19830
19840
19850
19860
19870
19880
19891
19906
19912
19924
199318
19940
19952
19961
19971
19981
19990
20000
20010
20020
20030
20041
20050
20060
20070
20081
20090
20100
20111
20120
20130
20140
20150
20160
20170
Total41