However, the notion of "Spanishness" would remain at the top and "Indianness" would be at the bottom, with those mixed being somewhere in the middle. This idea remained officially in force through the rest of the colonial period. Criollo resentment of the privileges afforded to the "Peninsulares" was the main reason behind the Mexican War of Independence. When the war ended in 1821, the new Mexican government expelled the peninsulares (approximately 10,000 – 20,000 people) in the 1820s and 1830s which at a degree, kept the European ethnicity from growing as a percentage; this expulsion however, did not lead to any permanent ban on European immigrants, even from Spain. Independence did not do away with economic and social privilege based on race as the Criollos took over those of Spanish birth. A division between "Spanish" and "indigenous" remained with Criollos distinguishing themselves from the rest of society as the guardians of Spanish culture as well as the Catholic religion. Due the abolition of the caste system the division, however, became more about money and social class and less about biological differences which widened the possibilities of social mobility for Mestizo and Indigenous Mexicans. For this reason many of the political and cultural struggles of the latter 19th and early 20th centuries would be between the Criollos and the Mestizos. According to Mexico's first ever racial census published in 1793, the Eurodescendant population was between 18%-22% of the population (with Mestizos being 21%-25% and Amerindians being 51%-61%) but by 1921, when the second nationwide census that considered a person's race took place, only 9% of the population self identified as being of European descent, with 59% being Mestizo and 29% being Amerindian. While for a long time the 1921 census' results were taken as fact, with international publications such as "The World Factbook" and Encyclopædia Britannica using them as a reference to estimate Mexico's racial composition up to this day, in recent time Mexican academics have subjected them to scrutiny, claiming that such a drastic alteration on demographic trends is not possible and cite, among other statistics the relatively low frequency of marriages between people of different continental ancestries. The authors claim that the Mexican society went through a "more cultural than biological mestizaje process" sponsored by the state which resulted on the inflation of the percentage of the Mestizo Mexican group at the expense of the identity of other races.