The question then becomes why some countries fail to reap the benefits of trade, whether by increasing their exports or their imports. We can distinguish between two broad sets of impediments - external and internal. A recent study has concluded that the worst of the barriers to merchandise trade (in agriculture and textiles) are particularly harmful to the world's poorest people, as are barriers to worker migration across borders (Anderson and Winters, 2008). As a result, the mean trade-weighted average tariff in OECD countries on imports from other OECD countries stands at 3%, as opposed to 4.8% on imports from non-OECD countries. In 2002, Bangladesh was charged the same amount of tariffs (around USD300 m) on its two and a half billion dollars of exports to the United States as France, whose exports were worth USD 30 billion.