Benoit Coeure, member of the Executive Board of the European Central Bank (ECB), gestures during the session 'The Global Economic Outlook' in the Swiss mountain resort of Davos January 24, 2015. REUTERS/Ruben Sprich

Republican presidential nominee Donald Trump hugs two Medal of Honor recipients before delivering remarks at a campaign event at the Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar

U.S. Democratic presidential candidate Hillary Clinton speaks at the Black Women's Agenda Annual Symposium in Washington, U.S., September 16, 2016. REUTERS/Carlos Barri4

Republican presidential nominee Donald Trump walks with former New York City Mayor Rudolph Giuliani (L) and his son Eric Trumo (R) through the new Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar

Republican presidential nominee Donald Trump reacts as reporters yell questions to him after he stated that he believes U.S. President Barack Obama was born in the United States at a campaign event at the Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar

Republican presidential nominee Donald Trump states that he believes U.S. President Barack Obama was born in the United States at a campaign event at the Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar

U.S. Democratic presidential candidate Hillary Clinton leaves after speaking at the Black Women's Agenda Annual Symposium in Washington, U.S., September 16, 2016. REUTERS/Carlos Barria

Republican presidential nominee Donald Trump's campaign plane (L) sits on the same tarmac as Democratic nominee Hillary Clinton's campaign plane (R), at Washington National airport in Washington, U.S., September 16, 2016. REUTERS/Carlos Barria