The greatest inequality between rich and poor among OECD countries was found in Mexico, where the wealthiest 10 percent of households had more than 25 times greater income than the poorest ten percent. In Turkey, the ratio was 17 to one, while the U.S. was just below that, at 16 to one.

The average for all 30 OECD nations in 2005 was about nine to one, with the smallest gap, less than five to one, found in Sweden and Denmark.

After Mexico and Turkey, the U.S. also has the highest poverty rate of the 30 OECD nations, according to the report, which defined poor households as those whose income was less than half of the media income in each of the member-countries.

For all OECD countries, the average poverty rate was just under 10 percent in 2005. In Mexico, the rate was highest at more than 20 percent. Turkey and the U.S. were tied at 17 percent. Lowest poverty rates were found in Denmark, Sweden, the Czech Republic, Austria, and Norway.