*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19846
19850
19864
19870
19882
19891
199010
19913
199212
19935
19943
19953
19961
19970
19980
19991
20001
20015
20020
20035
200449
20050
20060
20070
200811
20090
201020
201141
20120
20132
20141
20150
20167
20173
Total196