*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19905
19917
199215
19932
19945
19956
19966
19977
19988
199912
20004
200111
20024
200315
200416
200516
200624
200710
200826
200916
20107
20111
20122
20135
20140
20150
20160
20170
Total231