The investment seeks as high rate of income exempt from federal income taxes as is consistent with prudent investment management. The fund invests primarily in a diversified selection of municipal bonds (for example, general obligation bonds of a state or bonds financing a specific project) with maturities of one to seventeen years. A majority of the fund's investments are in issues with maturities longer than five years. It normally invests at least 70% of its total assets in municipal bonds rated A or better by Moody's or S&P, meaning that up to 30% of the fund's total assets may be invested in medium and lower-quality bonds.