*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
197510
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19903
19910
19925
19934
19940
19958
19960
19971
19981
19993
20005
20012
20023
200311
20046
20052
20061
20070
20081
20093
20101
20112
20120
20130
20140
20150
20160
20170
Total72