*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197210
19732
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19856
19860
19871
198820
19891
199025
199196
19927
199316
19941
19950
19960
199714
19980
199930
200030
200130
20023
20032
20040
20051
20060
20073
20085
20090
20101
20112
20120
20130
20140
20150
20167
20170
20180
Total313