*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
19900
19910
19920
19934
19940
19950
19960
19970
19981
19991
20000
20011
20020
20035
20042
20054
20061
200716
200814
20096
20104
20118
201210
20135
20140
20150
20160
20170
Total82