The World Bank publishes 'Atlas' conversion rates. These are three year averages of market exchange rates adjusted for relative inflation. As such they show trends in market rates, short term fluctuation in rate (very common in market exchange rates) being smoothed out. $US dollar rates are commonly used.
Inflation is removed from the series by adjusting each rate with its inflation relative to the rest of the world (as measured by SDR exchange rates).
Series adjusted by Atlas rates can show truer data than those adjusted by straightforward market exchange rates but, especially for poor countries, series will be very different from PPP adjusted data (see next section). PPP adjustment is considered to give a better reflection of price level changes for many purposes.
Atlas rates are used by the World Bank for a number of purposes, including setting the terms of lending. The Bank uses PPP conversion rates for much of its analytical work.
