Table 1.

Age, number and response rates of the study participants

Baseline year	Age at follow-up in 2001 (years)	Age at baseline (years)	Number of participants		Response rate (%)
			Boys	Girls	Boys	Girls
1979	37	14	564	535	86	91
	39	16	528	577	83	91
	41	18	528	512	78	86
1981	35	14	488	548	87	92
	37	16	535	529	85	92
	39	18	518	524	81	88
1983	33	14	429	482	79	86
	35	16	414	511	75	91
		18	–a	–a	–	–
1985	31	14	395	433	75	88
	33	16	455	499	77	87
	35	18	408	470	67	83
1987	29	14	1,674	1,789	81	89
	31	16	1,383	1,479	80	89
	33	18	1,012	1,274	74	89
1989	27	14	360	431	75	90
	29	16	362	380	70	82
	31	18	326	407	63	80
1991	25	14	1,629	1,837	74	87
	27	16	1,562	1,912	71	87
	29	18	1,286	1,626	61	82
1993	23	14	1,861	2,008	75	88
	25	16	1,655	1,943	71	87
	27	18	1,460	1,791	67	84
1995	21	14	1,177	1,301	75	85
	23	16	1,232	1,469	72	88
	25	18	1,071	1,313	67	86
1997	19	14	1,168	1,346	69	84
	21	16	1,126	1,379	68	87
	23	18	1,088	1,414	60	83
Total			26,688	30,719	72	87

^aIn 1983 no persons aged 18 were included in the sample