*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19841
19850
19860
19872
19889
19892
199010
19917
19923
19936
19945
19953
19960
19974
19983
19990
20000
20011
20023
200340
20040
20052
20066
20071
20085
20090
20100
20111
20120
20130
20140
20150
20161
20170
Total116