9. Income per Unit

The following is a summary of basic and diluted income per unit (in thousands, except unit and per unit amounts):



	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012

Net income available to common unitholders—basic	$ 141,629	$ 47,189	$ 233,123	$ 131,668

Add: Interest and amortization of debt issuance costs on 2029 Debentures	4,050	-	-	-
Net income available to common unitholders—diluted	$ 145,679	$ 47,189	$ 233,123	$ 131,668

Weighted average units outstanding—basic	130,977,193	126,242,751	130,287,383	117,291,480
Potentially dilutive common units:
Stock options	58,150	76,774	64,767	74,462
Unvested incentive units	132,195	250,316	119,583	205,247
Effect of dilutive 2029 Debentures	6,683,976	-	-	-

Weighted average units outstanding—diluted	137,851,514	126,569,841	130,471,733	117,571,189

Income per unit:
Basic	$ 1.08	$ 0.37	$ 1.79	$ 1.12
Diluted	$ 1.06	$ 0.37	$ 1.79	$ 1.12

We have excluded the following potentially dilutive securities in the calculations above as they would be antidilutive or not dilutive:



	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012

Potentially dilutive 2029 Debentures	-	6,514,812	6,628,489	6,471,282
Potentially dilutive Series C Cumulative Convertible Preferred Units	-	-	-	1,087,398
Potentially dilutive Series D Cumulative Convertible Preferred Units	-	4,219,384	629,389	4,309,978
Potentially dilutive Series E Cumulative Redeemable Preferred Units	5,251,059	4,151,146	4,853,976	4,045,501
Potentially dilutive Series F Cumulative Redeemable Preferred Units	3,330,210	2,632,647	3,078,381	1,243,998
Potentially dilutive Series G Cumulative Redeemable Preferred Units	4,553,517	-	2,918,921	-
	13,134,786	17,517,989	18,109,156	17,158,157