*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19721
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19894
19905
19912
19922
19936
19943
199526
19960
19978
19983
199910
20002
20013
20021
20030
20042
200511
20060
20070
20082
20090
20100
20110
20120
20130
20140
20150
20165
20170
Total96