STOCK-BASED COMPENSATION

6 Months Ended

Jun. 30, 2011

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION

6.     STOCK-BASED COMPENSATION

• The following summary sets out the activity with respect to the Company's outstanding stock options:

	Six months ended June 30, 2011
	# of Options			Weighted average exercise price
				(C$)
Outstanding, beginning of period		6,762,704			56.94
Granted		2,593,785			76.46
Exercised		(217,388	)		40.46
Cancelled		(91,750	)		66.87
Outstanding, end of period		9,047,351			62.83
Options exercisable at end of period		5,518,997			58.94

• For the six months ended June 30, 2011 and 2010, the Company estimated the fair value of options under the Black-Scholes option pricing model using the following weighted average assumptions:

	2011		2010
Risk-free interest rate		1.96%		1.87%
Expected life of options (in years)		2.5		2.5
Expected volatility of the Company's share price		34.6%		44.3%
Expected dividend yield		0.88%		0.43%