The duration of the trial was 12 months with a baseline survey and 2 follow-up surveys at approximately 6 and 12 months. The baseline study was conducted between May 28 and July 30, 2003. The 6 mo and 12 mo follow-up surveys were conducted between December 2003 and February 2004 and between June and July 2004, respectively. The mean time between the baseline and the 6 mo follow up was 5.4 mo and from the 6 to the 12 mo follow was 6.8 months.