Consider this situation in Bruinlandia (a hypothetical middle-income country). In 1990, 10% of the adult population had obtained a college degree. By 2015, 50% of the adult population had obtained a college degree. During this same time period, the average salary earned by a college-educated person compared to a non-college-educated person decreased in relative terms. For this situation, the credential obtained from a college education can best be characterized as what type of economic good