*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19731
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19906
19915
199212
19933
19947
19958
199613
199712
19985
19996
20006
200114
20027
200330
200434
200526
200625
200719
200841
200914
20109
20113
201211
201310
20140
20150
20160
20170
Total327