Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. estimated Reference, How Many Adults in the U.S. 242 million adults Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. 242 million adults Reference, How Many Adults in the U.S. Reference, How Many Adults in the U.S. 19-year-olds