A nuTonomy self-driving taxi drives on the road during its public trial in Singapore August 25, 2016. REUTERS/Edgar Su/File Photo

People are reflected in a screen displaying the Nikkei average outside a brokerage in Tokyo, Japan April 19, 2016. REUTERS/Thomas Peter

Ryan Tedder of the U.S. band OneRepublic performs during their "Native" tour in Riga November 12, 2014. REUTERS/Ints Kalnins/File Photo

Police in riot gear gather as they prepare for another night of protests over the police shooting of Keith Scott in Charlotte, North Carolina, U.S. September 22, 2016. REUTERS/Mike Blake

Four thousand U.S. dollars are counted out by a banker counting currency at a bank in Westminster, Colorado November 3, 2009. REUTERS/Rick Wilking/File Photo

Civilians breathe through an oxygen mask at al-Quds hospital, after a hospital and a civil defence group said a gas, what they believed to be chlorine, was dropped alongside barrel bombs on a neighbourhood of the Syrian city of Aleppo, Syria, early August 11, 2016. REUTERS/Abdalrhman Ismail

NASA scientists Lisa Danielson (L) and Will Stepanov are celebrated onstage for their wedding anniversary during the 26th First Annual Ig Nobel Prize ceremony at Harvard University in Cambridge, Massachusetts, U.S. September 22, 2016, fifteen years after they were married during an IgNobel prize ceremony. REUTERS/Brian Snyder

A line of SUV's making up Republican presidential nominee Donald Trump's motorcade navigate through rush hour traffic on Interstate 95 on their way to a rally with supporters in Aston, Pennsylvania, U.S. September 22, 2016. REUTERS/Jonathan Ernst