*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19831
19840
19850
19863
19870
19886
19893
199014
199114
199213
199311
199413
199523
199624
199720
199818
19999
20004
20010
20025
20031
20048
20053
20063
20072
20084
20091
20104
20118
20120
20130
20140
20150
20160
20170
Total216