On Wednesday, U.S. President Barack Obama met with Canadian Prime Minister Justin Trudeau and Mexican President Enrique Peña Nieto in Ottawa. This marks the first time Canadian, U.S., and Mexican leaders have met since 2014, as 2015's summit was not arranged in the harsh political relations at the time. Among the topics discussed were trade and the countries' economies, and current world events such as the U.S. presidential candidates and the United Kingdom's recent vote to leave the European Union. North America has a combined economy representing over 25% of the world's GDP (gross domestic product) with a little over 7% of the world's population. The countries' combined GDP has risen since 1993 from US$8 trillion to about US$20 trillion in 2016. The "Three Amigos" have shown an agenda geared towards green energy: pledging to generate 50% clean power across North America by the year 2025, implement a joint study about the addition of renewable energy sources in North America, and implement ten energy-efficiency standards and tests on equipment being traded throughout the continent. Trade was also a big topic of discussion, with the leaders affirming support not only for NAFTA (North American Free Trade Agreement) — something controversial in the U.S. political campaign — but also the Trans-Pacific Partnership (TPP), with Mexican President Peña Nieto stating: "We are fully convinced that by working together [...] we can be the most competitive region in the world". Justin Trudeau also said by December 1 of this year Mexicans will no longer require visas in order to come to Canada. The leaders held a trilateral press conference with the media after the summit. During the conference, President Obama scorned presidential candidate Donald Trump, calling his rhetoric "nativism or xenophobia".