What is the applicable interest on a judgment from March 28, 1980 to date of payment?

In light of the judgment in Lewis v. Todd, I would allow interest on the plaintiff's judgment from March 28, 1980, which was the last date of the trial hearing, to the date of payment. Where there was actuarial evidence of a prevalent interest rate in the range of 13%, it is not certain that the learned trial Judge accepted that figure in reaching his calculation of a net discount rate. Rather, it appears that the learned trial Judge was impressed by the evidence of the economist that historically, the difference between prevalent interest rate and the rate of inflation tended to settle in the range of 3 to 4%. Under the circumstances, I would allow interest on the judgment from trial to date of payment at a rate of 11%, "not as interest on the sum awarded but as part of the sum awarded".