The Chinese central bank on Tuesday set the weakest yuan reference rate against the U.S. dollar in more than 11 years, after the country's currency was sold amid the escalating trade war with the United States.The People's Bank of China set its daily reference rate at 6.9683, the lowest since May 2008, signaling that the central bank has started trying to bolster exports to shore up the economy. The rate was down 0.66 percent from the previous day.The yuan is allowed to trade up or down by 2 percent around the reference rate.On Monday, the U.S. Treasury Department said it has designated Chi…READ FULL ARTICLE