Section 6I. Interest required to be paid by the commonwealth pursuant to this section shall be calculated at a Weekly average one-year constant maturity Treasury yield, as published by the Board of Governors of the Federal Reserve System, for the calendar week preceding date of the judgment; provided, however, that such interest shall not exceed the rate of ten percent per annum. The secretary of administration and finance shall maintain a schedule of the rate described above for the distribution to all clerks of courts.