Some have disputed the attribution of the decline to Proposition 13's role in the change to state financing of public schools, because schools financed mostly by property taxes were declared unconstitutional (the variances in funding between lower and higher income areas being deemed to violate the Equal Protection Clause of the Fourteenth Amendment to the Constitution) in "Serrano vs. Priest", and Proposition 13 was then passed partially as a result of that case. California's spending per pupil was the same as the national average until about 1985, when it began decreasing, which resulted in another referendum, Proposition 98, that requires a certain percentage of the state's budget to be directed towards public education.