U.S. consumer credit increased at an annual rate of 8 percent in May as consumers stepped up their borrowing, the U.S. Federal Reserve reported on Monday.

Total consumer borrowing rose by 17.1 billion U.S. dollars to 2. 573 trillion dollars in May, a much faster growth pace than the previous month, the central bank said in a report.

Revolving debt, the category which includes credit cards, jumped 8 billion dollars to 870.2 billion dollars in May. The borrowing in the non-revolving category that includes auto loans rose 9.1 billion dollars to 1,702.6 billion dollars.

Consumer spending, which accounts for about 70 percent of the overall U.S. economic activity, is the major engine of U.S. economic growth.