*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
19884
19890
19900
19910
19927
19931
19941
199536
19960
19973
19984
19992
20000
20014
20021
20030
200439
200518
20063
20071
20087
20090
20103
20116
20120
20130
20140
20150
20161
20170
Total141