By Lucia Mutikani WASHINGTON, Aug 13 (Reuters) - U.S. producer prices were unchanged in July as goods prices fell and the cost of services increased marginally, bolstering financial market expectations that the Federal Reserve could keep interest rates unchanged next month.

Wholesale prices were unchanged last month, with help from lower energy costs, the Labor Department said.

This comes after the Midwest saw a massive spike in over-the-year percent changes in May, which saw high energy costs, according to the BLS.