Already the longest-lived of the 45 men to serve as U.S. president, Jimmy Carter has reached the century mark.The 39th president, who remains under home hospice care, turned 100 on Tuesday, celebrating in the same south Georgia town where he was born in 1924.Here are some notable markers for Carter, the nation and the world over his long life.Booms most everywhere — but not PlainsCarter has seen the U.S. population nearly triple. The U.S. has about 330 million residents; there were about 114 million in 1924 and 220 million when Carter was inaugurated in 1977. The global population has more than quadrupled, from 1.9 billion to more than 8.1 billion. It already had more than doubled to 4.36 billion by the time he became president.That boom has not reached Plains, where Carter has lived more than 80 of his 100 years. His wife Rosalynn, who died in 2023 at age …