Currency watchers have decreed that the euro will fall sharply against the dollar as Europe and the United States’ monetary policies diverge, but history suggests the euro’s drop may not be quite so smooth or rapid. As a result the euro has fallen nearly 10 percent against the dollar since mid-May. Goldman Sachs predicts a further 20 percent fall to parity by the end of 2017, Deutsche is going for a 25 percent slide to $0.95 and almost every other major financial institution expects further weakness to some degree.