*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19772
19780
19790
19800
19810
19820
19830
19840
19851
19860
19870
19880
19890
19901
19914
19927
19935
19941
199516
199635
199715
19983
19992
20002
20010
20023
20032
20040
20054
20061
20070
20080
20091
20100
20110
20121
20130
20140
20150
20160
20170
Total106