TORONTO, March 6 (Reuters) - Canada's main stock index climbed on Wednesday with gold-mining shares leading the way on higher bullion prices and sentiment getting a boost from U.S. economic data and central banker comments. The Toronto Stock Exchange's S&P/TSX composite index unofficially closed up 95.92 points, or 0.75 percent, at 12,831.96. Eight of the 10 main sectors on the index were higher.