Fig. 3. Income level and distribution, 1970 and 2000 (Barro and Sala-i-Martin 2004). The data used are adjusted to 1985 prices and to purchasing power parity and draw on Penn World Tables (see http://datacentre2.chass.utoronto.ca/pwt/). From "Ecosystems and Human Well-being: Scenarios, Volume 2" by Steve R. Carpenter, et al., eds. Copyright (c) 2005 Millennium Ecosystem Assessment. Reproduced by permission of Island Press, Washington, D.C.