*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19840
19853
19860
19875
19882
19891
19902
19910
19920
19930
19940
19951
19960
19974
19982
19991
20000
20012
20020
20030
20040
20051
20060
200711
20081
20091
20103
20110
20120
20131
20140
20150
20160
20170
Total42