Another ethnic group in Mexico, the Mestizos, is composed of people with varying degrees of European and indigenous ancestry, with some showing a European genetic ancestry higher than 90%. However, the criteria for defining what constitutes a Mestizo varies from study to study, as in Mexico a large number of white people have been historically classified as Mestizos, because after the Mexican revolution the Mexican government began defining ethnicity on cultural standards (mainly the language spoken) rather than racial ones in an effort to unite all Mexicans under the same racial identity.