WASHINGTON, Dec. 12 — PRIME. The next two or three years may be the worst for the world economy due to the excessive amount of accumulated debts, well-known American investor Jim Rogers said. Rogers is one of the most famous investors in the world and co-founder of the Quantum investment fund, which he created together with billionaire George Soros. Rogers is the author of a number of books about investing. The Rogers International Commodity Index (RICI) is named after him. "The next...