Over the past 32 years, the economy of Thailand has expanded. The GDP at current prices shows that from 1980 to 2012 the Thai economy has expanded nearly sixteen-fold when measured in baht, or nearly eleven-fold when measured in dollars. This makes Thailand the 32nd-biggest economy in the world, according to the IMF. With regard to GDP, Thailand has undergone five periods of economic growth. From 1980 to 1984, the economy has grown by an average of 5.4 percent per year. Regional businesses account for 70 percent of GDP, with Bangkok contributing 30 percent.