*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19840
19850
19860
19870
19880
19890
19900
19910
19921
19931
199410
199547
19961
19975
199814
19990
20008
20010
20020
20030
20041
20051
20063
20070
20084
20091
20101
20111
20120
20130
20140
20150
20160
20170
Total100