*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19870
19885
19890
19905
19910
19922
19930
19941
199539
19961
199725
19983
19996
20000
20013
20020
20032
200434
20056
20060
20072
200815
20090
201019
201131
20122
20132
20140
20150
20163
20170
Total207