*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
19860
19870
198825
19897
19900
19912
19926
19938
19940
19958
19962
19975
19982
19992
20002
20011
20021
20038
20040
20050
20061
20071
20081
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total83