1993 1994 1995 1996
Total percent missing income 11.5
(11.2, 11.8) 		13.5
(13.2, 13.8) 		13.0
(12.7, 13.4) 		14.0
(13.7, 14.3)
Percent Don’t Know 5.4
(5.2, 5.6) 		5.7
(5.5, 6.0) 		6.4
(6.1, 6.6) 		6.6
(6.4, 6.8)
Percent refused 6.1
(5.6, 6.3) 		7.8
(7.5, 8.0) 		6.7
(6.4, 6.9) 		7.4
(7.2, 7.6)