*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19902
19913
19926
19933
19941
19952
19966
19972
19982
19994
20001
200110
20022
200316
200416
20059
200633
200720
200840
20096
20109
20113
20129
201311
20140
20150
20160
20170
Total216