The extent to which a country trades with the rest of the world depends on many factors. Small countries, measured in this instance by population size, tend to trade more than larger ones, as they cannot efficiently produce the full range of consumer goods, intermediate products, and capital equipment demanded by consumers and businesses. Just as a small town cannot offer the same range of stores and services for shopper as a large town, small economies cannot efficiently produce everything that households and firms would like to buy, so they tend to import more products to satisfy those demands. On the export side, as firms in small economies increase production, they are more likely to be constrained by the limited size of the market and unable to take advantage of economies of scale if they sell only locally. By exporting to global markets, they can sell larger amounts of more-specialized products. Export earnings then pay for the imports small nations demand. Producers in larger economies can sell a much larger share of their output locally without being constrained by market size. In Guyana, with a population of under 1 million, imports and exports together exceed 200 percent of GDP; in Mauritius they reach 133 percent. But in much larger Brazil and India, the ratios are 27 and 45 percent, respectively. Figure 18-4 confirms this relationship across all countries. It helps explain why sub Saharan Africa, which has a large number of nations, half of them with populations below 10 million, has such a relatively high ratio of trade to GDP.