*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
19901
19910
19921
19930
19943
19953
19960
19976
19980
19993
20000
20010
20020
20030
20040
20050
20060
20070
20080
20090
201052
201148
20122
20139
201413
20151
20161
20170
Total143