It may be a matter of semantics, but UFO stands only for "unidentified flying objects." People see inexplicable objects in the sky all the time--some of these people include experienced pilots like Japan's Kenju Tarauchi and Iran's General Parviz Jafari, who had terrifying up close encounters with unknown aircraft. Five percent or so of these are never explained. So UFOs unequivocally exist, and the percentage of people who acknowledge that should be 100%.