Table 1.

Estimated Cumulative Probability of Illegal Drug Use, Sexual Intercourse, Tobacco and Alcohol Use by Age for Females and Males, Among a Sample of African American College Students on HBCU Campuses Who Had Not Initiated Illegal Drug Use Before age 14 (n=7,372).

	Total (n=7,372)		Female (n=4,775)		Male (n=2,597)
	%	95% CI	%	95% CI	%	95% CI
Age at first illegal drug use (yrs)
14-15	8.6	8.0 - 9.3	7.1	5.7- 7.1	14.1	11.5-14.1
16-17	20.8	19.9-21.7	18.1	16.0-18.1	29.5	26.1-29.5
18-20	26.0	25.0-27.0	23.6	21.2-23.6	34.6	30.9-34.6
Age at first sexual intercourse (yrs)
13 or younger	13.5	12.8-14.3	8.1	7.4- 8.9	23.5	21.9-25.2
14-16	51.7	50.5-52.8	44.0	42.6-45.4	65.8	64.0-67.7
17-19	76.0	75.0-77.0	72.6	71.4-73.9	82.2	80.7-83.6
Age at first tobacco use (yrs)
Under 10	1.4	1.1- 1.7	1.1	0.9- 1.5	1.8	1.4- 2.4
10-11	3.0	2.6- 3.4	2.7	2.3- 3.2	3.4	2.8- 4.2
12-13	7.0	6.4- 7.6	6.4	5.7- 7.1	8.1	7.1- 9.2
14-15	14.4	13.6-15.2	12.4	11.5-13.4	17.9	16.5-19.5
16-17	23.3	22.3-24.3	20.4	19.2-21.5	28.7	27.0-30.5
18-20	27.2	26.2-28.2	24.2	23.0-25.5	32.6	30.8-34.5
Age at first alcohol use (yrs)
Under 10	4.7	4.3- 5.3	4.2	4.2- 5.4	4.8	4.0- 5.7
10-11	7.6	7.0- 8.3	6.9	6.9- 8.4	7.6	6.6- 8.7
12-13	13.6	12.8-14.4	12.4	12.4-14.4	13.9	12.6-15.3
14-15	25.9	24.9-26.9	23.7	23.7-26.2	27.6	25.9-29.4
16-17	46.8	45.7-48.0	44.9	44.9-47.7	47.8	45.9-49.8
18-20	57.2	56.0-58.3	56.0	56.0-58.8	56.8	54.9-58.7