The U.S. Congressional Budget Office sees the U.S. budget surpluses growing to $5.6 trillion over the next decade, steadily growing from $281 billion this year to $889 billion in 2011 -- allowing all the public debt that can be paid down to be redeemed by 2006, Capitol Hill aides said Tuesday night. The notion that the U.S. public debt could be retired to an irreducible minimum of less than $1.3 trillion as early as 2006 was first raised by Federal Reserve Chairman Alan Greenspan in testimony to the Senate Budget Committee last week.