*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
19893
19900
199132
19920
19934
19941
19956
19960
19970
19980
19991
20002
20011
20020
200340
20040
20052
20060
20070
20085
20091
20100
20110
20120
20131
20140
20151
20160
20170
20180
20190
20200
Total100