The age-old fixation. Hitting 100 rotations around the sun is no small feat, with just an estimated 101,000 centenarians , representing 0.03% of the US population. New research , though, may have cracked the code for why some live to triple digits, and others don’t. Lifestyle habits are often the primary drivers of longevity, such as regular exercise and healthy eating, as well as genetics playing a role. Researchers from the University of Geneva and the University of Lausanne in Switzerland