Socio-demographic characteristics

<16 years

16 < x < 18 years

>18 years

Mean age

14.6 years

16.9 years

20.6 years

Gender (male/female)

21/2

7/3

8/1

Education level

low 7, middle 9, high 7

Low 3, middle 4, high 3

Low 3, middle 3, high 3

Average family size

4.1

4.0

2.7