*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19831
19840
19850
19860
19870
198815
19892
19905
19913
19929
199315
19941
19953
19960
19972
19987
19994
20003
20012
20020
20034
20040
20053
20060
20070
20084
20090
20101
20110
20120
20130
20142
20150
20160
20170
Total87