<P> It has been estimated that over 1.86 million Spaniards emigrated to Latin America in the period between 1492 and 1824, with millions more continuing to immigrate following independence . </P> <P> In Hispaniola, the indigenous Taíno pre-contact population before the arrival of Columbus of several hundred thousand had declined to sixty thousand by 1509 . Although population estimates vary, Dominican friar Bartolomé de las Casas, the "Defender of the Indians" estimated there were 6 million (6,000,000) Taíno and Arawak in the Caribbean at the time of Columbus's arrival in 1492 . </P> <P> The population of the Native American population in Mexico declined by an estimated 90% (reduced to 1--2.5 million people) by the early 17th century . In Peru the indigenous Amerindian pre-contact population of around 6.5 million declined to 1 million by the early 17th century . The overwhelming cause of the decline in both Mexico and Peru was infectious diseases, although the brutality of the Encomienda also played a significant part in the population decline . </P> <P> Of the history of the indigenous population of California, Sherburne F. Cook (1896--1974) was the most painstakingly careful researcher . From decades of research he made estimates for the pre-contact population and the history of demographic decline during the Spanish and post-Spanish periods . According to Cook, the indigenous Californian population at first contact, in 1769, was about 310,000 and had dropped to 25,000 by 1910 . The vast majority of the decline happened after the Spanish period, during the Mexican and US periods of Californian history (1821--1910), with the most dramatic collapse (200,000 to 25,000) occurring in the US period (1846--1910). </P>

When did the spanish decided to explore north america