"As of June 2011, the U.S. Treasury calculates that $230 million in United States notes are in circulation, and excludes this amount from the statutory debt limit of the United States. This amount excludes $25 million in United States Notes issued prior to July 1, 1929, determined pursuant to Act of June 30, 1961, 31 U.S.C. 5119, to have been destroyed or irretrievably lost.
[link to www.treasurydirect.gov]