*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19850
19860
19870
198811
19890
19904
199115
19923
19936
19943
19959
199622
199713
19982
19993
20000
20011
20021
20030
20040
20050
20061
20070
20084
20090
20106
20112
20120
20130
20140
20150
20160
20170
Total107