9. Notes Payable

The following is a summary of our indebtedness:

		September 30,		September 30,
	December 31,
(in millions)	2011		2010
Commercial Banks
Unsecured line of credit and short-term borrowings	$	—	$	—
Term loan, due 2012		—		500.0

	$	—	$	500.0
Senior unsecured notes
7.69% Notes, due 2011		—		88.0
5.93% Notes, due 2012		189.6		189.5
5.45% Notes, due 2013		199.7		199.6
5.08% Notes, due 2015		249.3		249.2
5.75% Notes, due 2017		246.2		246.1
4.70% Notes, due 2021		248.6		—
5.00% Notes, due 2023		247.3		—

		1,380.7		972.4
Medium-term notes
4.99% Notes, due 2011		—		35.4


Total unsecured notes payable		1,380.7		1,507.8

Secured notes
0.91% – 6.00% Conventional Mortgage Notes, due 2012 – 2045		1,012.3		1,015.7
1.59% Tax-exempt Mortgage Note, due 2028		39.1		40.3

		1,051.4		1,056.0

Total notes payable	$	2,432.1	$	2,563.8

Floating rate tax-exempt debt included in secured notes (1.59%)	$	39.1	$	40.3
Floating rate debt included in secured notes (0.91% – 1.73%)		206.4		189.9
Value of real estate assets, at cost, subject to secured notes		1,651.0		1,629.6

In September 2011, we amended our $500 million unsecured credit facility to extend the maturity date from August 2012 to September 2015 with an option to extend to September 2016. Additionally, we now have the option to increase this credit facility to $750 million by either adding additional banks to the credit facility or obtaining the agreement of existing banks to increase their commitments. The interest rate is based upon LIBOR plus a margin which is subject to change as our credit ratings change. Advances under the line of credit may be priced at the scheduled rates, or we may enter into bid rate loans with participating banks at rates below the scheduled rates. These bid rate loans have terms of 180 days or less and may not exceed the lesser of $250 million or the remaining amount available under the line of credit. The line of credit is subject to customary financial covenants and limitations, all of which we are in compliance.

Our line of credit provides us with the ability to issue up to $100 million in letters of credit. While our issuance of letters of credit does not increase our borrowings outstanding under our line of credit, it does reduce the amount available. At December 31, 2011, we had outstanding letters of credit totaling approximately $10.4 million, leaving approximately $489.6 million available under our unsecured line of credit.

In June 2011, we issued from our existing shelf registration statement $250 million aggregate principal amount of 4.625% senior unsecured notes due June 2021 (the "2021 Notes") and $250 million aggregate principal amount of 4.875% senior unsecured notes due June 2023 (the "2023 Notes" and, together with the 2021 Notes, the "Notes"). The 2021 Notes were offered to the public at 99.404% of their face amount with a yield to maturity of 4.70% and the 2023 Notes were offered to the public at 98.878% of their face amount with a yield to maturity of 5.00%. We received net proceeds of approximately $491.8 million, net of underwriter discounts and other offering expenses. Interest on the Notes is payable semi-annually on June 15 and December 15, beginning December 15, 2011. We may redeem each series of Notes, in whole or in part, at any time at a redemption price equal to the principal amount and accrued interest of the notes being redeemed, plus a make-whole provision. If, however, we redeem Notes of either series 90 days or fewer prior to their maturity date, the redemption price will equal 100% of the principal amount of the Notes to be redeemed plus accrued and unpaid interest on the amount being redeemed to the redemption date. Each series of Notes is a direct, senior unsecured obligation and ranks equally with each other and with all of our other unsecured and unsubordinated indebtedness. We used the proceeds from this offering, together with cash on hand, to repay our outstanding $500 million term loan. In conjunction with the repayment of the $500 million term loan, we expensed approximately $0.5 million of unamortized loan costs.

As part of the 2005 Summit merger, we assumed certain debt and recorded approximately $33.9 million as a fair value adjustment which is being amortized over the respective debt terms. As of December 31, 2011, the fair value adjustment was fully amortized. We recorded amortization of the fair value adjustment, which resulted in a decrease of interest expense of approximately $0.4 million, $1.1 million, and $2.3 million during the years ended December 31, 2011, 2010, and 2009, respectively.

At December 31, 2011 and 2010, the weighted average interest rate on our floating rate debt, which includes our unsecured line of credit, was approximately 1.1% and 1.3%, respectively.

Our indebtedness, including our unsecured line of credit, had a weighted average maturity of 6.8 years at December 31, 2011. Scheduled repayments on outstanding debt, including all contractual extensions which have been exercised, including our line of credit and scheduled principal amortizations, and the weighted average interest rate on maturing debt at December 31, 2011 were as follows:

		September 30,		September 30,
(in millions)	Amount		Weighted Average Interest Rate
2012	$	294.2		5.2	%
2013		228.0		5.4
2014		11.0		6.0
2015		252.4		5.1
2016 (1)		2.6		N/A
2017 and thereafter		1,643.9		4.6

Total	$	2,432.1		4.8	%

(1)

Includes only scheduled principal amortizations.