*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19811
19820
19830
19840
19850
19861
19873
19881
19890
19903
19914
19920
19933
19940
19950
19960
19971
19980
19990
20000
20010
20021
20030
20040
20050
20060
20070
20080
20090
20102
20113
20120
20130
20140
20151
20165
20171
20180
Total30