(1) The maximum effective rate of interest per annum for home loans is hereby set at an amount equal to two (2) percentage points above the most recent weighted average yield of the accepted offers of the Federal National Mortgage Association's current free market system auction for commitments to purchase conventional home mortgages (FNMA Auction) as determined pursuant to § 47-15-103.
(2) In the event the Federal National Mortgage Association discontinues the conduct of the auction, the maximum effective rate of interest per annum for home loans shall be set at an amount equal to four (4) percentage points above the index of market yields of long term government bonds adjusted to a thirty (30) year maturity by the department of the treasury.
(3) The maximum effective rate of interest per annum for home loans shall not, in any event, exceed eighteen percent (18%) per annum.