Global investment demand for gold jumped 70% year on year in 2016 to the highest level in four years, buoyed in part by the uncertain path of future interest-rate increases and the U.S. election, according to a report from the World Gold Council released Friday. Investment demand of the yellow metal rose to 1,561.1 metric tons in 2016, from 918.7 metric tons a year earlier, and inflows of gold into exchange-traded funds for the year were at their strongest since 2009, the WGC said.