*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197211
197318
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19871
198817
19899
199013
199159
19926
19934
19941
19950
19966
19971
19980
19993
20000
20010
20020
20030
20041
20050
20060
20073
20086
20090
20101
20110
20120
20132
20140
20152
20169
20171
20180
Total174