A view shows the U.S. Food and Drug Administration (FDA) headquarters in Silver Spring, Maryland August 14, 2012. REUTERS/Jason Reed/File Photo

City workers walk past the Bank of England in the City of London, Britain, March 29, 2016. REUTERS/Toby Melville/File Photo

A shopkeeper sells groceries to a customer at his shop in Kolkata, India, September 12, 2016. REUTERS/Rupak De Chowdhuri

Students throw stones during clashes with security at Johannesburg's University of the Witwatersrand. Demonstrations this year and in 2015 over the cost of university education -- prohibitive for many black students -- have highlighted frustration at the inequalities that persist more than two decades after the 1994 end of white minority rule. REUTERS/Siphiwe Sibeko

A view shows the U.S. Food and Drug Administration (FDA) headquarters in Silver Spring, Maryland August 14, 2012. REUTERS/Jason Reed/File Photo

Iraq's Finance Minister Hoshiyar Zebari speaks during a news conference in Baghdad January 21, 2016. REUTERS/Khalid al-Mousily

UEFA President Aleksander Ceferin during the launch. UEFA EURO 2020 Launch Event - London City Hall - 21/9/16. Action Images via Reuters / Tony O'Brien Livepic

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