Table 1.

 Number of specimens per site

Year	No. sites USA	No. sites Mexico	Enrollees USA	Enrollees Mexico
2004–2005	1	0	122	0
2005–2006	2	0	224	0
2006–2007	3	0	207	0
2007–2008	4	2	243	143
2008–2009	12	2	506	410
Total			1302	553