*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
19872
19881
19890
19900
19913
19922
19932
19941
19951
19961
19972
19981
19990
20002
20010
20020
20030
20040
20051
20060
20070
20080
20090
20100
201146
20122
20135
20140
20150
20161
20170
20180
Total73