The US has abundant natural resources, a well-developed infrastructure, and high productivity.[38] It has the world's ninth-highest per capita GDP (nominal) and tenth-highest per capita GDP (PPP) as of 2013.[39][40] Americans have the highest average household and employee income among OECD nations, and in 2010 had the fourth highest median household income, down from second highest in 2007.[41][42] It has been the world's largest national economy (not including colonial empires) since at least the 1890s.[43]