Table 1.

Sample sizes by demographics and questionnaire

Demographics		N	%
Race		17,979
	Asian	366	2.0
	African-American/ Black	874	4.8
	Native American	99	0.5
	Native Hawaiian	17	0.1
	White/Caucasian	14,053	77.8
	Other	643	3.6
	More than one	1927	10.7
Geographic region		50,376
	Urban	43,877	87.1
	Rural	6499	12.9
Biological parent marital status		11,950
	Married	7932	66.4
	Divorced	1598	13.4
	Separated	382	3.2
	Never married	2038	17.1
Annual household income (in thousands of U.S. dollars)		18,049
	Less than 20	2189	11.8
	21–35	2607	14.1
	36–50	2505	13.5
	51–65	1876	10.1
	66–80	1969	10.6
	81–100	2054	11.1
Questionnaires		N (% F)	M age in years (SD)
	Individual data	18,502 (20.6)	8.88 (4.19)
	Background and history	18,042 (20.6)	8.56 (4.15)
	Basic medical screening	30,943 (18.36)	8.73 (4.23)
	SCQ	19,657 (20.2)	8.59 (4.17)