The first census in Mexico (then known as New Spain) that included an ethnic classification was the 1793 census. Also known as the Revillagigedo census. Most of its original datasets have reportedly been lost, thus most of what is known about it nowadays comes from essays and field investigations made by academics who had access to the census data and used it as reference for their works such as German scientist Alexander von Humboldt. Europeans ranged from 18% to 22% of New Spain's population, Mestizos from 21% to 25%, Indians from 51% to 61% and Africans were between 6,000 and 10,000. The total population ranged from 3,799,561 to 6,122,354. It is concluded that the population growth trends of whites and mestizos were even, while the percentage of the indigenous population decreased at a rate of 13%–17% per century, mostly due to the latter having higher mortality rates from living in remote locations and being in constant war with the colonists. Independent-era Mexico eliminated the legal basis of the Colonial caste system which led to exclusion of racial classification in the censuses to come.