By John S. McClenahen Even as the U.S. economy begins to show some signs of a stronger economic recovery from recession, Germany, once Europe's driving economic force, continues to lag behind. The latest index of leading economic indicators for Germany compiled by the Conference Board, a New York-based business research group, fell 0.1% in May to 99.6 (1990=100). The index had risen 0.3% in April and fallen 0.5% in March. The leading index signals near-term economic direction. "The weakness in the leading index remains widespread," says the Conference Board.