R.I. Gen. Laws § 29-6-2: Public library services.

For each city or town, the state’s share to support local public library services shall be equal to at least twenty-five percent (25%) of both the amount appropriated and expended in the second preceding fiscal year by the city or town from local tax revenues and funds from the public library’s private endowment that supplement the municipal appropriation; provided, however, the state in any year shall not be obligated to match any amount from the endowment that exceeds six percent (6%) of the three-year (3) average market value, calculated at the end of the calendar year, of the investments in the endowment. The amount of the grant payable to each municipality in any year in accordance with this section shall be reduced proportionately in the event that the total of those grants in any year exceeds the amount appropriated that year for the purposes of this section.