CANADA STOCKS-TSX records biggest monthly drop since May 2012

* TSX down 16.41 points, or 0.11 percent, at 14,960.51 * Five of 10 main index sectors decline * Selloff in oil price weighs on energy shares By John Tilak TORONTO, Sept 30 (Reuters) - Canada's main stock index posted its biggest monthly decline since May 2012 in September, losing about 4.3 percent, as a stronger U.S. dollar weighed on commodity prices and shares of natural resource companies. The market was little changed on Tuesday as softness in the energy and materials s