Both the Renegade period and the Apache Wars ended in 1924 and brought the American Indian Wars to a close. The 2010 United States Census found 2,932,248 Americans who identified themselves as being American Indian or Alaskan Native, about 0.9% of the US population. The Canada 2011 Census found 1,836,035 Canadians who identified themselves as being First Nations (or Inuit or Métis), about 4.3% of the Canadian population. No consensus exists on how many people lived in the Americas before the arrival of Europeans, but extensive research continues to be conducted. Contemporary estimates range from 2.1 million to 18 million people living on the North American continent prior to European colonization with the bulk living south of the Rio Grande, but the US Census Bureau stated in 1894 that North America was an almost empty continent in 1492 and that Indian populations "could not have exceeded much over 500,000." The number of Indians dropped to below half a million in the 19th century because of infectious diseases, conflict with Europeans, wars between tribes, assimilation, migration to Canada and Mexico, and declining birth rates. The main cause was infectious diseases carried by European explorers and traders. The United States Census Bureau (1894) provided their estimate of deaths due specifically to war during the 102 years between 1789 and 1891, including 8,500 Indians and 5,000 whites killed in "individual affairs":  The Indian wars under the government of the United States have been more than 40 in number. They have cost the lives of about 19,000 white men, women and children, including those killed in individual combats, and the lives of about 30,000 Indians. The actual number of killed and wounded Indians must be very much higher than the number given ... Fifty percent additional would be a safe estimate. According to historian David Rich Lewis, American popular histories, film, and fiction have given enormous emphasis to the Indian wars. New ethno-historical approaches became popular in the 1970s which mixed anthropology with historical research in hopes of gaining a deeper understanding of the Indian perspective. During the 1980s, human rights abuses by the US government were increasingly studied by historians exploring the impact of the wars on Indian cultures. Prior to this, popular history was heavily influenced by Dee Brown's non-academic treatment of historical events in "Bury My Heart at Wounded Knee" (1970). In more academic history, Francis Jennings's "The Invasion of America: Indians, Colonialism, and the Cant of Conquest" (New York: Norton, 1975) was notable for making strong attacks against the Puritans and rejecting the traditional portrayal of the wars between the Indians and colonists.