*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
19860
19870
19884
19890
19900
19916
19925
19936
19941
19956
19960
19973
19980
19990
20000
20010
20020
20032
20040
20050
20060
20070
20080
20090
20101
20110
20121
20130
20140
20150
20161
20170
Total37