With a total of 1.28 million cosets solved, we have shown that every position of Rubik's cube can be solved in 22 or fewer face turns.
This required approximately 50 core-years of CPU time contributed by John Welborn and Sony Pictures Imageworks.
No distance 21 positions were found in this search, despite solving a total of more than twenty-five million billion cube positions.
There is a short article in New Scientist (August 9th edition) on this problem and this result.
The same techniques for the proof of twenty-five moves were used, just on many more computers.
I have found 310 cosets with an upper bound of 18, and about 82,000 with an upper bound of 19 (or less); all the rest have an upper bound of 20 or less.
My most profound thanks to John Welborn, Sony Pictures Imageworks, Herbert Kociemba, and Silviu Radu, and any others who have helped me over the past couple of years.