§ 198. Interest on damages for change of grade. Whenever awards shall be lawfully made, pursuant to any statute of this state, for damages sustained by real estate or any improvements thereon by reason of any change of grade of any street, avenue or road in front thereof, the award for the principal amount of damages sustained shall bear interest at the rate of six per centum per annum from the time of the change of grade to the time of the payment of the award.