The first trade surplus in petroleum in more than forty years helped the U.S. post a lower trade deficit in September compared to August, but overall U.S. exports and imports in all sectors also declined as trade spats, tariffs, and slowing global growth weighed on trade. For the first time since 1978, the U.S. recorded a surplus in the petroleum trade, at US$252 million in September, government data showed on Tuesday. The value of petroleum exports stood at US$14.966 billion, while imports were at US$14.714 billion. Both exports and imports in…