Domestic cats are found across the globe, though their popularity as pets varies by region. Out of the estimated 600 million cats worldwide, 400 million reside in Asia, including 58 million pet cats in China. The United States leads in cat ownership with 73.8 million cats. In the United Kingdom, approximately 10.9 million domestic cats are kept as pets. The origin of the English word cat, Old English catt, is thought to be the Late Latin word cattus, which was first used at the beginning of the 6th century.The Late Latin word may be derived from an unidentified African language. The Nubian word kaddîska (wildcat) and Nobiin kadīs are possible sources or cognates.