WASHINGTON (MarketWatch) - The U.S. trade deficit sank 17% in February to the lowest level since 2009, largely because of cheaper oil, but exports also fell to a two-and-a-half year bottom in a sign that a stronger dollar and a weak global economy are hurting American companies. The U.S. trade deficit declined by $7.2 billion to $35.4 billion in February from a revised $42.7 billion in January, the Commerce Department said Thursday. Economists surveyed by MarketWatch forecast a deficit of $41.7 billion. The smaller trade gap is a mixed blessing. The sharp drop is likely to boost first-quarter gross domestic product, but weaker exports could be a drag on the economy in the months ahead. Exports dropped 1.6% to $186.2 billion, the smallest amount since October 2012. The U.S. exported less oil, aircraft, computer chips and soybeans, among other things. Imports fell an even sharper 4.4% to $221.7 billion, the lowest in almost three years. Petroleum imports tumbled to the lowest level since 2004, but the U.S. also ordered fewer foreign-made cell phones, electronics, computers and industrial machines.