The estimated long-term average annual returns are nominal (no adjustment for inflation). The stock returns (U.S. and international) and T-bill return are from Siegel's Stocks for the Long Run, with the latter based on the period of 1946-1997. The municipal bond estimate is based on Siegel's 1946-1997 data for long-term U.S. Treasury bonds, reduced by a point to account for a spread between Treasuries and municipals.