The peak Indigenous population in Queensland prior to European arrival is uncertain. The number may have been between 200,000 and 500,000 people. Numbers may have decreased at times of epidemics like smallpox. Rough calculations of the population can be made from the knowledge that Queensland supported 34.2 per cent of the total number of tribes in Australia and from the knowledge that 35 to 39 per cent of Australian indigenous people lived in Queensland. Queensland was the most densely populated region of the continent with two of the six to seven hundred Indigenous nations and at least ninety language groups.