The official numbers on their homepage show that in 2005, 53% of state inmates were sentenced for violent crimes, versus only 20% for drug crimes.
http://www.ojp.usdoj.gov/bjs/prisons.htm
Note that the statistics only count the most serious of the offenses for which the person was sentenced, which means that some of the violent offenders may have also been charged with drug crimes.
(This is simply to demonstrate a logical contradiction in your proposed evidence, and is not intended to make a factual argument.)
If so I'd have to dispute it. I do think the U.S. imprisons too many people for drug charges but I also think China and Russia have a lot of people imprisoned "off the books". Also keep in mind the statistics don't tell the whole story. We all know Russia doles out a lot of punishment via hit squad and China, who won't release their capital punishment numbers, admits to executing more people than any other country on earth (though not per capita thanks to Iran)
If China has fewer people in prison because the execute far more people than your argument isn't really a valid one
IIRC, even China doesn't have as many people in jail as the US.