Growth of the German economy, Europe's biggest, picked up fractionally at the end of last year, propelled by buoyant exports, official data showed on Friday. German gross domestic product (GDP) grew by 0.4 percent in the period from October to December, slightly faster than analysts' expectations and also up from growth of 0.3 percent in the preceding three months, the federal statistics office Destatis said. "Positive impulses came primarily from net foreign trade," Destatis explained. "According to preliminary calculations, exports grew much more strongly than imports. By contrast, the signals from domestic demand were more mixed," the statisticians said. Public spending stagnated and consumer spending was down slightly, but positive developments were seen in investment. Investment in both construction and equipment was up strongly, but companies also sharply reduced their stockpiles "and that put the brakes on growth," Destatis said. Taking 2013 as a whole, Destatis confirmed a preliminary estimate from last month which showed that German growth slowed to just 0.4 percent last year, the slowest growth for four years.