An epizootic outbreak of equine influenza during 1872 in North America became known as "The Great Epizootic of 1872". The outbreak is known as the "most destructive recorded episode of equine influenza in history". In 1870, three fourths of Americans lived in rural areas (towns under 2,500 population, and farms). Horse and mule power was used for moving wagons and carriages, and pulling plows and farm equipment. The census of 1870 counted 7.1 million horses and 1.1 million mules, as well as 39 million humans. With most urban horses and mules incapacitated for a week or two, humans used wheelbarrows and pulled the wagons. About 1% of the animals died, and the rest fully recovered.