TORONTO (Reuters) - Canada's main stock index opened slightly higher on Monday, as strong Chinese economic data helped to offset concerns about a possible U.S. fiscal crisis and delays to an installment of Greek aid. The Toronto Stock Exchange's S&P/TSX composite index opened up 19.50 points, or 0.16 percent, at 12,216.30. (Reporting by Claire Sibonney; Editing by Jeffrey Hodgson)