The American Kennel Club carries out an annual analysis of registration numbers in order to determine the most popular dog breeds in the United States. Some breeds have proven consistently popular for years. In 2002, Labrador Retrievers were the most popular dog breed in the United States and they are still topping the charts a decade later.Interestingly, the Chihuahua and the Shih Tzu have completely disappeared from the 2012 top 10 list, though both breeds proved highly popular back in 2002. Larger dog breeds are enjoying something of a surge these days, with Bulldogs and Rottweilers making steady gains in the popularity stakes.The former has even managed to muscle its way into the top five. Back in 2002, the Bulldog was outside the top 10! So it might be time for Paris Hilton and her Chihuahua to move aside and make way for the modern Americans out walking their German Shepherds, Boxers and Rottweilers.