Romney's influence grew while he positioned himself as chief spokesman of the automobile industry, often testifying before Congressional hearings about production, labor, and management issues; he was mentioned or quoted in over 80 stories in "The New York Times" during this time. By war's end, 654 manufacturing companies had joined the Automotive Council for War Production, and produced nearly $29 billion in output for the Allied military forces. This included over 3 million motorized vehicles, 80 percent of all tanks and tank parts, 75 percent of all aircraft engines, half of all diesel engines, and a third of all machine guns. Between a fifth and a quarter of all U.S. wartime production was accounted for by the automotive industry.