BERLIN—German exports increased for the third consecutive month in December, capping a year in which they rose 14 percent compared with 2020, official figures showed Wednesday. The Federal Statistical Office said that exports from Germany, Europe’s biggest economy, were up 0.9 percent in December compared with the previous month. That followed gains of 1.8 percent in November and 3.9 percent in October. Imports were up 5.7 percent in December, their fifth consecutive monthly increase. For 2021 as a whole, exports rose 14 percent to some 1.38 trillion euros ($1.57 trillion), the statistics office said. Imports were up 17.1 percent at over 1.2 trillion euros ($1.37 trillion). The United States remained Germany’s top export destination, with China second and France third. China was the biggest source of imports to Germany, followed by the Netherlands and the U.S. Trade with Britain was a notable exception to the upward trend in the first …