The cause of population decline among the indigenous inhabitants of the Americas after the coming of Christopher Columbus has long been attributed to the advent of the European epidemic diseases. These diseases were smallpox, influenza, measles, typhus, cholera, mumps, yellow fever, pneumonia, whooping cough, and tuberculosis, which were chronic in Europe and Asia. The combined impact of all these diseases was to cause the deaths of 80 to 90 percent of the indigenous American population within about 100 years. Estimates of the pre-Columbian population in the Americas are uncertain, but a number of 50 million is possible. By 1650, only about eight million were left.