*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19852
19860
19871
19888
19898
19902
199112
19920
199311
19940
19950
19962
19972
19981
19990
20001
20010
20020
20030
20040
20050
20060
20071
20080
20090
20101
20110
20120
20130
20140
20150
20162
20170
20180
Total55