*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19902
19910
19923
19933
19947
19958
19960
19970
19980
19991
20001
20011
20021
20032
200432
20050
20060
20070
20086
20090
201027
201127
20121
20130
20140
20150
20161
20170
Total124