The euro zone's trade surplus grew year-on-year in May in a sign net trade made a positive contribution to economic growth in the second quarter, the European Union's Statistics Office data showed. The external trade surplus of the 18 countries sharing the euro, unadjusted for seasonal swings, was 15.4 billion euros ($20.87 billion) in May, up from 14.6 billion euros in the same period of 2013, the data showed. Analysts polled by Reuters had expected a 16.5 billion euro surplus compared with the originally reported surplus of 15.7 billion euros in April, which was revised down to 15.4 billion. The euro zone's economic recovery, which relies heavily on exports, is sensitive to swings in demand for euro zone goods and the relative strength of the euro currency has not made life easier for exporters. The European Central Bank President Mario Draghi said on Monday that any further appreciation of the single currency could stall the recovery. Non-seasonally adjusted exports and imports were unchanged year-on-year in May. Month-on-month and adjusted for seasonal factors, exports increased 0.6 percent and imports grew 0.5 percent, both showing the first increase in three months. The trade surplus in the first five months of the year widened to 62.5 billion euros form 55.4 billion euros in the same period of 2013. Exports to Russia, the euro zone's fourth biggest trade partner, fell 13 percent on the year in the first four months of the year, while exports to the bloc's top three business partners - United Kingdom, the United States and China were up. Germany, the euro zone's main export country, saw exports rising 2 percent on the year in the January-April period and imports growing 3 percent. The southern periphery saw export activity stalling, with Spain and Portugal showing no growth in exports in the first four months and Greece reporting a fall of 8 percent on the year. Trade deficits in all three countries widened in the January-April period. (Reuters)