Percentage of the US population carrying cameras everywhere they go, every waking moment of their lives: 
[[A graph with years from 1975 to 2013 as the X axis and a percentage from 0 to 100 as the Y axis.  The sole line starts at just above 0, jumps to 1-2 at around 2000, is at 10% at 2005, 75% at 2010, and around 90% at 2013]]
In the last few years, with very little fanfare, we've conclusively settled the questions of flying saucers, lake monsters, ghosts, and Bigfoot.

{{Title text: Well, we've really only settled the question of ghosts that emit or reflect visible light. Or move objects around. Or make any kind of sound. But that covers all the ones that appear in Ghostbusters, so I think we're good.}}