Role of the US Financial System

Several years ago, an article in the Economist stated, “. . . foreign central banks seem to have reduced their purchases of American Treasuries: official holdings of these rose by only $2 billion in the first seven months of 2005, against $295 billion in (the whole of) 2004 and $175 billion in 2003. If this trend continues, other currencies could one day challenge the dollar's dominance . . .”

Has this trend continued? What impact might such a reduction in purchases of U.S. treasury securities have on the cost of short- and long-term financing? If the central bank of another country increases interest rates, how does that affect purchase of American Treasuries?

Does Turkey purchase American Treasuries? To what extent?