BEIJING (Reuters) - China's economy showed signs of slowing growth in September, the state statistics bureau said on Friday, after announcing that GDP grew 7.8 percent in the third quarter, its fastest pace this year and in line with expectations. National Bureau of Statistics spokesman Sheng Laiyun told a news briefing that net exports had subtracted 0.1 percentage point from growth in the first three months of the year. (Reporting by China Economics Team; Editing by Paul Tait)