*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19836
19841
19853
19863
198747
19883
198913
19902
19910
19921
19930
19941
199530
19960
19979
19982
19992
200010
20013
20020
20031
20044
20054
20065
200735
200814
200914
201014
20114
20120
20130
20142
20151
20160
20170
Total234