The Friday File: According to the National UFO Reporting Center, in 1990 there were 315 global UFO sightings. Sightings then steadily rose, reaching 2,000 in 1998, over 4,000 in 2003, and peaked at 8,670 in 2014. Sightings have since plummeted. In 2017 they totaled 5,000, and this year are on a pace to hit 2,600. Maybe extraterrestrials have improved their antidetection technology, or maybe they have tired of studying us?