The Great Depression was a severe worldwide economic event in the decade preceding World War II. Beginning in 1929 in most countries, it continued through the late 1930s or early 1940s. The U.S. stock market crash of October 29, 1929, is credited as the starting point. Impact was devastating: unemployment in the United States rose to 25 percent, all forms of revenue and prices dropped, and international trade dropped by up to two-thirds. Construction was nearly halted and crop prices fell to below half their prices before the market crash. U.S. recovery began in 1933, but the gross national product did not return to pre-depression levels until the 1940s.