*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19836
19840
19850
198611
19871
19881
198917
19902
19913
199222
19939
19946
199510
19961
19976
19981
19990
20002
20013
20020
20036
200446
200513
20061
20073
200812
20090
20102
20110
20120
20130
20140
20151
20164
20170
Total190