When the tax levied by AS 43.56.010(a) becomes delinquent, a penalty of 10 percent shall be added. Before January 1, 2014, interest on the delinquent taxes, exclusive of penalty, shall be assessed at a rate of eight percent a year. On and after January 1, 2014, interest on the delinquent taxes, exclusive of penalty, shall be assessed at the rate specified in AS 43.05.225.