Public water fluoridation was first practiced in 1945, in the US. As of 2012, 25 countries have artificial water fluoridation to varying degrees, 11 of them have more than 50% of their population drinking fluoridated water. A further 28 countries have water that is naturally fluoridated, though in many of them the fluoride is above the recommended safe level.[25] As of 2012 about 435 million people worldwide (around 5.4% of the global population) received water fluoridated at the recommended level,[25] nearly half of them living in the United States.[26]