* TSX down 73.86 points, or 0.52 percent, at 14,245.14 * Nine of the 10 main index sectors decline * Empire Co drops after posting results * Cameco gains as production starts at Cigar Lake mine By John Tilak TORONTO, March 13 (Reuters) - Canada's main stock index fell on Thursday with almost every major sector declining as worries grew about soft economic data from China and the crisis in Ukraine. Russia conducted military exercises near its border with Ukraine, while U.S. Secretary of State John Kerry said serious measures would be taken by the United States and Europe if the referendum on Crimea joining Russia takes place on Sunday as planned. In China, growth in investment, retail sales and factory output slipped to multiyear lows, reinforcing concerns raised by a recent wave of weak economic figures in the world's second-biggest economy. Data showing that the number of Americans filing new claims for unemployment benefits dropped to a three-month low last week failed to brighten the mood. But one group, gold-mining stocks, continued its march higher, jumping 2.3 percent as investors looked for safety in bullion amid the uncertainty. The sector gained for a third straight session and is up about 35 percent since the start of the year. Despite Thursday's decline, the Toronto stock market's benchmark index is up about 4.5 percent this year, increasing concern among some investors that the runup might result in a correction. "Today's action seems to be driven not just by the ongoing situation in Ukraine but also this spate of soft data that continues to come out of China," said Elvis Picardo, strategist at Global Securities in Vancouver. "Those concerns are an overhang." "Both are wildcard events that could drive the markets much lower from these levels," he added. "But conversely, if things get better, they would turn out to be classic buying opportunities." The Toronto Stock Exchange's S&P/TSX composite index was down 73.86 points, or 0.52 percent, at 14,245.14. "I'm going to start taking profits in the next two to three weeks. Am I going to be bailing out totally? No," said Keith Richards, portfolio manager and technical analyst at ValueTrend Wealth Management. "You stick to the program, let the market climb the wall of worry and when you see the market start to roll over, then you can get out," he added. Nine of the 10 main sectors on the index were in the red on Thursday. Financials, the index's most heavily weighted sector, declined 0.8 percent, with Bank of Nova Scotia losing 0.8 percent to C$64.61 and Bank of Montreal dropping 1.2 percent to C$72.43. The energy group fell 0.2 percent, hurt by a decline in the price of Brent crude. Suncor Energy Inc was down 1.2 percent at C$36.25, and Canadian Natural Resources Ltd lost 1 percent to C$39.45. In corporate news, Empire Co Ltd dropped about 3 percent to C$68.10 after the operator of the Sobeys grocery chain posted a fall in quarterly earnings late on Wednesday. Shares of Cameco Corp advanced 2.7 percent to C$27.63 after the uranium miner said it had begun producing ore at its often-delayed Cigar Lake mine in northern Saskatchewan.