Well, there is no quick answer, because there's an endless number of steps, processes, and safeguards that we build into everything we do, including the last time, when we had the census in 2006. We ordered a security audit in which basically we mandated security firms who specialize in “white hat” hacking, as it's called, to try to hack into the database to try to penetrate our security. They couldn't.
On July 27th, 2010. See this statement in context.