Table 1.

20-m SRT (number of laps) centiles by age and sex for 69,960 Chinese children and youth aged 9–17 years.

	Age(yr)	P5	P10	P20	P30	P40	P50	P60	P70	P80	P90	P95
Boy	9	8	10	13	15	18	20	23	26	29	35	40
	10	9	12	15	18	21	23	26	30	34	41	47
	11	11	14	18	21	24	27	30	34	39	47	53
	12	13	16	20	24	28	31	35	39	45	53	61
	13	14	18	23	27	31	35	40	45	51	60	69
	14	16	20	26	30	35	39	44	49	56	67	76
	15	17	22	28	33	37	42	47	53	60	72	82
	16	19	23	29	35	40	44	50	56	64	75	86
	17	19	24	31	36	41	46	52	58	66	78	89
Girls	9	8	10	13	15	17	19	21	24	27	32	37
	10	10	12	14	17	19	21	24	27	31	36	42
	11	11	13	16	19	21	24	26	30	34	40	46
	12	12	14	17	20	23	26	29	32	36	43	50
	13	12	15	19	22	24	27	30	34	39	46	52
	14	13	16	20	23	26	29	32	35	40	48	55
	15	14	16	20	23	26	29	33	37	41	49	56
	16	14	17	21	24	27	30	33	37	42	50	57
	17	14	17	21	24	27	31	34	38	43	50	58

Ages shown represent age at last birthday (e.g. 9 = 9.0–9.99).