From the Huffington report:
Of the known space rocks, the next time an object will get closer to Earth will be in 2029 when an 885-foot asteroid called 99942 Apophis comes within 20,000 miles, said Donald Yeomans of NASA's Near-Earth Object Program at the Jet Propulsion Laboratory in Pasadena.
The important qualification does not address the fact there are many NEOs (Near Earth Objects) that are not known or identified. It is these rogue objects that pose the most worrisome threat. Every year that goes by sees improvements and advancements in mapping the sky to find these objects but I think most astronomers will acknowledge that the time and attention devoted to it is woefully inadequate.