The Bank of England is seen in the City of London in London, Britain August 4, 2016. REUTERS/Neil Hall/File Photo

The logo of the Organization of the Petroleum Exporting Countries (OPEC) is pictured at its headquarters in Vienna, Austria, August 21, 2015. REUTERS/Heinz-Peter Bader

French Finance Minister Michel Sapin responds to a question as he attends the questions to the government session at the National Assembly in Paris, France, June 22, 2016. REUTERS/Jacky Naegelen

Roofers work on new homes at a residential construction site in the west side of the Las Vegas Valley in Las Vegas, Nevada April 5, 2013. REUTERS/Steve Marcus

Damaged aid trucks are pictured after an airstrike on the rebel held Urm al-Kubra town, western Aleppo city, Syria September 20, 2016. REUTERS/Ammar Abdullah

Damaged Red Cross and Red Crescent medical supplies lie inside a warehouse after an airstrike on the rebel held Urm al-Kubra town, western Aleppo city, Syria September 20, 2016. REUTERS/Ammar Abdullah

Traders work on the floor of the New York Stock Exchange (NYSE) in New York City, U.S., September 15, 2016. REUTERS/Brendan McDermid

The former Anglican archbishop of Cape Town Desmond Tutu waits to receive the 2013 Templeton Prize at the Guildhall in central London in this file photo dated May 21, 2013. REUTERS/Paul Hackett/File Photo