Yuan's Role in China Trade Grows Quickly‎

7% of China's trade in the first quarter was in Yuan, up from .5% a year earlier. 

Yuan's Role in China Trade Grows Quickly‎ - Wall Street Journal


And with the decrease in the US dollar for commodity pricing (Oil and minerals) and worries of inflation in China, I would not be surprised if the amount of trade done in Yuan grows quickly. The pricing of Gold is a great indicator of the fear of a weak dollar.

I agree with this article, I would not be surprised if there was a revaluation soon for the Yuan. Waiting for a Chinese Curve Ball - WSJ


http://www.dagongcredit.com/dagongweb/uf/USARatingReport.pdf
From the actual report - a depressing read, but interesting the Chinese view on the US:

My guess this is both a political as well as economic statement.

•  “AA” to “A+“ downgrade US debt repayment capability.
• new round of quantitative easing monetary policy adopted by the Federal Reserve has brought about an obvious trend of depreciation of the U.S. dollar
• An overall crisis might be triggered by the U.S. government’s policy to continuously depreciate the U.S. dollar against the will of creditors.
• Due to the abuse of credit, the United States became a net debtor country in 1985.