*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197219
19735
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19855
19861
19875
198833
198917
199031
199117
19929
19934
19940
19951
19960
19971
19980
199920
200014
200110
200210
20031
200434
20050
20061
20070
200811
20090
20101
20112
20120
20130
20140
20150
20162
20171
20180
20190
Total256