After World War I, the American Saddlebred began to be exported to South Africa, and it is now the most popular non-racing breed in that country. Saddlebred horse show standards continued to evolve through the 1920s, as the popularity of the breed grew. The Saddlebred industry slowed during World War II, but began to grow again post-war, with Mexico, Missouri earning the title "Saddle Horse Capital of the World". Exports continued, and though attempts to begin a South African breed registry had started in 1935, it was not until 1949 that the Saddle Horse Breeders' Society of South Africa was formed. The 1950s saw continued growth of the Saddlebred breed, and The Lemon Drop Kid, a fine harness horse, became the first, and only, Saddlebred to appear on the cover of "Sports Illustrated". In the late 1950s, the Saddle Horse Capital became centered in Shelby County, Kentucky, largely due to the success of breeders Charles and Helen Crabtree, the latter a renowned equitation coach. Although individual Saddlebreds had been exported to Great Britain throughout the breed's history, the first breeding groups were transported there in 1966. For the next three decades, enthusiasts worked to establish a breeding and showing platform for the breed in the UK.