*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19871
19883
19892
19900
19912
199210
19935
19947
199545
19961
19974
199828
19996
20006
20013
20021
20031
20047
200519
20060
20071
20089
20090
201029
201137
20120
20131
20149
20150
20161
20170
Total238