Table 1

Breakdown of subject numbers for each year of testing and data points collected at each testing trial

			Data points at each testing trial
	Subject numbers		Initial year		Following year
	Boys	Girls	Trial 1	Trial 2	Trial 3	Trial 4
1991	294	217	240	252	74	98
1992	148	84	150	155	1	25
1993	164	86	2	184	76	55
1994	153	125	96	157	94	62
1995	189	185	279	258	43	33
1996	153	140	33	132	81	88
1997	227	150	133	164	78	60
1998	171	162	147	66	107	62
1999	191	149	130	162	104	26
2000	64	48	121	52
2003	96	110	206

Trials 1 and 2 correspond to February–April and October–November testing periods, respectively, in the first year of testing, and trials 3 and 4 correspond to the same testing periods in the following year. Data points do not always correspond to subject numbers since one subject may have as many as four individual data points (one in each trial).