Table 1.

Number of participants in each session by age group and sex.

Age group	Sex	S1	S2	S3	S4
2nd	Girl	503	496	474	454
	Boy	502	526	501	494
3rd	Girl	453	480	465	451
	Boy	510	499	498	474
4th	Girl	373	382	368	363
	Boy	355	365	350	321
		2696	2748	2656	2557

2nd, second grade at session 1 (7–8 years old); 3rd, third grade at session 1 (8–9 years old); 4th, fourth grade at session 1 (9–10 years old); S1, session 1; S2, session 2; S3, session 3; S4, session 4.