DEARBORN, Mich. — Ford Motor says its second-quarter profit dropped slightly as its costs rose and it continued to pay off debt.

The company earned $2.4 billion, or 59 cents per share, down 8 percent from $2.6 billion, or 61 cents per share, in the second quarter of 2010.

It was Ford’s ninth straight quarterly profit. Worldwide sales rose, but the company spent more on materials and product development.

Revenue rose 13 percent to $35.5 billion. Analysts polled by FactSet had forecast revenue of $32.15 billion.

Without one-time items, including $110 million for employee reductions, Ford would have earned $2.9 billion, or 65 cents per share. That beat analysts’ forecast of 60 cents per share.

Ford paid off $2.6 billion in debt during the quarter.