It’s been slow going. About 1.6 million of the group’s laptops have been distributed to date, said Matt Keller, vice president for global advocacy at the O.L.P.C. Foundation, based in Cambridge, Mass. Today, the largest concentrations are in Uruguay, at around 400,000, and Peru, at 280,000, followed by Rwanda (110,000) and Haiti and Mongolia (15,000 each).