*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19892
19902
19910
19921
19933
19944
19951
199621
199721
19988
19993
200021
200113
20021
20030
20040
20050
20060
20070
20080
20092
20103
20110
20120
20130
20141
20150
20160
20170
20185
Total112