Sample size: planned number of observations
The baseline survey in 2006 was administered to 1,231 households living in 1,193 dwellings, with a response rate of 94%. In 2009, 1,083 households were interviewed. In 900 cases we found the same household that we had interviewed in 2006, and in 156 cases we found that a new household was in residence. All families living in residences built between baseline and follow-up were also interviewed (N = 27).