*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19870
198811
19890
199010
19911
19926
19939
19945
199515
199610
199713
19983
19995
20000
20012
20025
20031
20041
20053
20061
20070
200811
20091
20103
20113
20120
20130
20141
20150
20160
20170
Total121