Also known as the "Revillagigedo census" from the name of the Count who ordered that it be conducted, this census was the first nationwide population census of Mexico (then known as the Viceroyalty of New Spain). Most of its original datasets have reportedly been lost, so 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 Prussian geographer Alexander von Humboldt. Each author gives different estimations for each racial group in the country although they don't vary greatly, with Europeans ranging from 18% to 22% of New Spain's population, Mestizos from 21% to 25%, Indians from 51% to 61%, and Africans from 6,000 and 10,000. The estimations given for the total population range from 3,799,561 to 6,122,354. It is concluded then, that across nearly three centuries of colonization, the population growth trends of whites and mestizos were even, while the total percentage of the indigenous population decreased at a rate of 13%–17% per century. The authors assert that rather than whites and mestizos having higher birthrates, the reason for the indigenous population's numbers decreasing lies in their suffering higher mortality rates due to living in remote locations rather than in cities and towns founded by the Spanish colonists or in being at war with them. For the same reasons, the number of Indigenous Mexicans presents the greatest variation range between publications, as in some cases their numbers in a given location were estimated rather than counted, leading to possible overestimations in some provinces and possible underestimations in others.