U.S. wholesale prices plunged 1.4% in February, the biggest decline in nearly three years, the Labor Department reported Tuesday. Energy prices fell 4.7%, also the biggest drop since April 2003. Food prices fell 2.7%, the most in four years. Economists expected the PPI to fall about 0.3%. The core producer price index - which excludes food and energy prices - rose 0.3%, stronger than the 0.1% gain expected by Wall Street economists. In the past year, the PPI has risen 3.7%. The core rate has accelerated to a 1.7% increase in the past 12 months