They are all the current members of CAFTA-DR. El Salvador became the first country to formally implement CAFTA, which went into effect on March 1, 2006, when the Organization of American States (OAS) received signed copies of the treaty. On April 1, 2006, Honduras and Nicaragua fully implemented the agreement. On May 18, 2006, the Congress of Guatemala ratified CAFTA-DR, which went into effect on July 1, 2006. The Dominican Republic implemented the agreement on March 1, 2007. In a referendum on October 7, 2007, Costa Rica narrowly backed the free trade agreement, with 51.6% voting "Yes"; the agreement took effect on January 1, 2009. The goal of the agreement is the creation of a free trade area similar to NAFTA, which currently encompasses the United States, Canada, and Mexico. CAFTA-DR is also seen as a stepping stone towards the FTAA, another (more ambitious) free trade agreement that would encompass all the South American and Caribbean nations as well as those of North and Central America except Cuba. Canada is negotiating a similar treaty called the Canada–Central American Free Trade Agreement. Once passed by the countries involved, tariffs on about 80% of U.S. exports to the participating countries were eliminated immediately and the rest were phased out over the subsequent decade. As a result, CAFTA-DR does not require substantial reductions in U.S. import duties with respect to the other countries, as the vast majority of goods produced in the participating countries already entered the United States duty-free due to the U.S. government's Caribbean Basin Initiative. With the addition of the Dominican Republic, the trade group's largest economy, the region covered by CAFTA-DR is the second-largest Latin American export market for U.S. producers, behind only Mexico, buying $29  billion of goods in 2015. Two-way trade amounted to about $50  billion in the same year. While not necessarily a part of Plan Puebla Panama, CAFTA is a necessary precursor to the execution of Plan Puebla Panama by the Inter-American Development Bank. The plan includes construction of highways linking Panama City to Mexico City, Texas, and the rest of the United States. CAFTA-DR reduces tariffs, but every CAFTA country sets its overall tax level. In January 2002 U.S. President George W. Bush declared CAFTA as a priority and received "fast track" authority from Congress to negotiate it.