GM began its "Keep America Rolling" campaign, which boosted sales, and other automakers were forced to follow suit. The U.S. automakers saw sales increase to leverage costs as gross margins deteriorated. For the first quarter of 2006, GM earned $400 million, signaling that a turnaround had already begun even though many aspects of the restructuring plan had not yet taken effect. Although retiree health care costs remain a significant issue, General Motors' investment strategy has generated a $17.1 billion surplus in 2007 in its $101 billion U.S. pension fund portfolio, a $35 billion reversal from its $17.8 billion of underfunding.