Table 1.

Distribution of age and sex of the students in Surabaya, 2017.

Characteristics	n	%
Age (years)
8–9	17	7.8
10–11	189	86.7
12–13	12	5.5
Total	218	100.0
Sex
Boys	84	38.5
Girls	134	61.5
Total	218	100.0