*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19800
19810
19820
19830
19846
19850
19863
198720
198811
19891
19905
199111
199210
199319
19943
199517
19964
19972
19987
19992
20005
20011
20029
20030
20041
20056
20061
20070
200816
20091
20102
20110
20121
20130
20141
20151
20160
20170
20181
Total168