*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19854
19861
19870
19880
19895
19900
19910
19923
19934
19944
199515
19960
199712
19981
199913
20001
20010
20023
20032
200431
20051
20060
20071
20080
20092
20103
20118
20120
20130
20140
20150
20160
20170
Total115