Table 2.

Description of study samples across survey years (population weighted), N = 3739

Independent variables		1987 (%)	1991 (%)	1995 (%)	2002 (%)	2005 (%)	2008 (%)	Total (N)	Missing (n)	Trend test (P)
	Standardized survey year	1986	1990	1994	2002	2005	2008	3739	0
Sex	Female	58	58	58	58	57	57			0.455
	Valid N	643	576	579	512	468	961	3739	0
Age group	67–74	55	54	51	42	43	45
	75–79	24	24	24	25	24	23
	80–84	14	14	16	20	20	18
	85+	7	8	9	13	13	15
	Valid N	643	576	578	511	468	961	3739	0	<0.001
Marital status	Married or cohabitating	56	53	57	55	55	59
	Valid N	644	560	577	512	468	961	3722	18	0.062
Educational level	Lower level (<9 years)	76	57	51	42	43	37
	High school level (10–13 years)	19	40	46	44	42	44
	University/college (>14 years)	5	4	3	14	14	19	3683	57	<0.001
	Valid N	639	567	574	504	464	935