*Excludes Observations that spanned multiple years

Pre 197053
19700
19711
19720
19731
19740
19751
19760
19770
19780
19790
19800
19811
19823
19830
19840
19851
19861
19870
19880
19890
19900
19910
19921
19930
19940
19950
19960
19970
19980
19990
20000
20010
20020
20030
20040
20050
20060
20070
20080
20090
20100
20110
20121
20130
20140
20150
20160
20170
Total64