Hope they don't have their 'meters' and 'feet' mixed up. (:-/
Get your crash helmets on!
Try 1908, Siberia.
Consider that two-thirds of the surface is ocean, which would mean the only evidence of such a hitg would be tidal waves. We might have no knowledge of the Siberian hit except for a few curious scientists. It wasn't even suspected of being a meteorite or comet until the 1950s.
The Tunguska event provided last century's hit. We're due for another on that scale. And there have been theories, which I consider somewhat outlandish, that the Peshtigo, Wisconsin fire that occurred on the same day as the Great Chicago Fire was caused by a meteorite event. That wouldn't constitute a major hit, but if true, that would be a hit for that century.
New Evidence (for comet/asteroid theory of fire triggering)
Finally, Earth is 70% ocean. Asteroid impacts hitting the ocean or Antarctica on the scale of a Tunguska may not have been recorded, or if related phenomena were observed and reported they may not be distinguishable from a large volcanic eruption.