The Labrador Retriever is the Most Popular Purebred Dog in America.
The AKC list the Labrador Retriever as the most popular purebred dog in America for the 18th consecutive year. You can see how the other breeds ranked on a national and state level by visiting the AKC American Kennel Club
Don't forget as Barrett Welch, DVM points out in this months veterinary article; "Contrary to most beliefs, one fourth of all shelter dogs are pure bred."