Long-term incentive plan

3 Months Ended

Mar. 31, 2012

Long-term incentive plan

Long-term incentive plan

9. Long-term incentive plan

        The following table summarizes the changes in LTIP notional units during the three months ended March 31, 2012:

	Units			Grant Date Weighted-Average Price per Unit
Outstanding at December 31, 2011		485,781		$	11.49
Granted		209,009		$	14.65
Additional shares from dividends		8,172		$	12.02
Vested		(231,687	)	$	10.10
Outstanding at March 31, 2012		471,275		$	13.81

        Certain awards have a market condition based on our total shareholder return during the performance period compared to a group of peer companies. Compensation expense for notional units granted in 2012 is recorded net of estimated forfeitures. See further details as disclosed in our Annual Report on Form 10-K for the year ended December 31, 2011.

        The calculation of simulated total shareholder return under the Monte Carlo model for the remaining time in the performance period for awards with market conditions included the following assumptions as of March 31, 2012 and December 31, 2011:

	March 31, 2012		December 31, 2011
Weighted average risk free rate of return		0.19 – 0.51%		0.15 – 0.28%
Dividend yield		8.30%		7.90%
Expected volatility—Company		22.2%		22.2%
Expected volatility—peer companies		17.1 – 112.8%		17.3 – 112.9%
Weighted average remaining measurement period		1.92 years		0.87 years