Economists generally agree that free trade increases the level of economic output and income, and conversely, that trade barriers reduce economic output and income. Historical evidence shows that tariffs raise prices and reduce available quantities of goods and services for U.S. businesses and consumers, which results in lower income, reduced employment, and lower economic output. The North American Free Trade Agreement (NAFTA) is between the United States, Canada, and Mexico, and is the world's largest free trade area. It eliminates all tariffs among the three countries, tripling trade to $1.2 trillion. The largest multilateral agreement is the North American Free Trade Agreement. It is between the United States, Canada and Mexico. Their combined economic output is $20 trillion. Over NAFTA's first two decades, regional trade increased from roughly $290 billion in 1993 to more than $1.1 trillion in 2016.