 The general law of comparative advantage theorizes that an economy should, on average, export goods with low self-sufficiency prices and import goods with high self-sufficiency prices.Bernhofen and Brown found that by 1869, the price of Japan's main export, silk and derivatives, saw a 100% increase in real terms, while the prices of numerous imported goods declined of 30-75%.In the next decade, the ratio of imports to gross domestic product reached 4%.