PROSPECTUS SUPPLEMENT NO. 1

Filed Pursuant to Rule 424(b)(7)

(To Prospectus Dated June 15, 2007)

Registration No. 333-143815

Name

Aggregate
Principal
Amount of
Notes That
May Be Sold

Percentage of
Notes
Outstanding

Number of
Shares of
Common Stock
That May Be
Sold (1)

Percentage of
Shares of
Common Stock
Outstanding

American Century Capital Portfolios, Inc. - Equity Income Fund

$

16,686,000

5.80

%

306,617

0.48

%

Board of Trustees of the Sheet Metal Workers Local Union No. 224

$

19,000

*

350

*

Brookline Avenue Master Fund, LP (2)

$

1,500,000

0.52

%

27,564

0.04

%

Credit Suisse Securities (USA) LLC (3)

$

6,000,000

2.09

%

110,255

0.17

%

Focused SICAV—Convert Global (EUR) (4)

$

12,600,000

4.38

%

231,534

0.37

%

Froley Revy Alternative Strategies

$

500,000

0.17

%

9,188

0.01

%

Morley AISF Convertible Bond Arbitrage Fund (5)

$

3,000,000

1.04

%

55,128

0.09

%

Privilege Portfolio SICAV (5)

$

6,000,000

2.09

%

110,255

0.17

%

S.A.C. Arbitrage Fund, LLC (6)

$

10,000,000

3.48

%

183,757

0.29

%

The Northwestern Mutual Life Insurance Company (7) (8)

$

3,500,000

1.22

%

64,315

0.10

%

UBS (Lux) Bond SICAV Convert Global USD B (4)

$

900,000

0.31

%

16,539

0.03

%

UBS Securities LLC (3) (9)

$

5,350,000

1.86

%

98,310

0.16

%

*

Less than 0.01%

(1)

Represents the maximum number of shares of our common stock issuable upon conversion of all of the holder’s notes, based on the initial conversion rate of 18.3757 shares of our common stock per $1,000

principal amount at maturity of the notes. However, this conversion rate will be subject to adjustment as described under “Description of Notes—Conversion Rights.” As a result, the amount of common stock issuable upon conversion of the notes may increase or decrease in the future.

(2)

This selling securityholder has advised us that voting power and investment control with respect to the notes and common stock held by this selling securityholder are exercised by Brookline Avenue Partners, LP, its investment advisor.

(3)

The selling securityholder is a broker-dealer.

(4)

This selling securityholder has advised us that voting power and investment control with respect to the notes and common stock held by this selling securityholder are exercised by Andreas Jacobs, Managing Director of UBS AG, Basel und Zürich (“UBS AG Basel”), Dirk Spiegel, Executive Director of UBS AG Basel, Gerhard Fusenig, Managing Director of UBS AG Basel, Gilbert Schintgen, Executive Director of UBS Fund Services (Luxembourg) S.A., Luxembourg (“UBS Luxembourg”), and Aloyse Hemmen, Executive Director of UBS Luxembourg.

(5)

This selling securityholder has advised us that voting power and investment control with respect to the notes and common stock held by this selling securityholder are exercised by David Clott.

(6)

This selling securityholder has advised us that, pursuant to investment agreements, each of S.A.C. Capital Advisors, LLC, a Delaware limited liability company (“SAC Capital Advisors”), and S.A.C. Capital Management, LLC, a Delaware limited liability company (“SAC Capital Management”), share all investment and voting power with respect to the notes and common stock held by this selling securityholder.  Mr. Steven A. Cohen controls both SAC Capital Advisors and SAC Capital Management.  Each of SAC Capital Advisors, SAC Capital Management and Mr. Cohen disclaim beneficial ownership of the notes and common stock held by this selling securityholder.

(7)

The Northwestern Mutual Life Insurance Company (“Northwestern Mutual”) has advised us that Northwestern Investment Management Company, LLC (“NIMC”), a wholly owned company of Northwestern Mutual, is one of the investment advisers to Northwestern Mutual and is the investment adviser to Northwestern Mutual with respect to the notes and common stock held by Northwestern Mutual. NIMC may be deemed to be an indirect beneficial owner with shared voting power and investment power with respect to the notes and common stock held by Northwestern Mutual. Jerome R. Baier is a portfolio manager for NIMC and manages the portfolio which holds the notes and common stock held by Northwestern Mutual. Jerome R. Baier may be deemed to be an indirect beneficial owner with shared voting power and investment power with respect to the notes and common stock held by Northwestern Mutual. Northwestern Mutual has advised us that, pursuant to Rule 13d-4 under the Securities Exchange Act of 1934 (the “Exchange Act”), the foregoing sentences shall not be construed as an admission that Jerome R. Baier is, for the purposes of Section 13(d) or 13(g) of the Exchange Act, the beneficial owner of any of the notes and common stock held by Northwestern Mutual. Northwestern Mutual has also advised us that Mason Street Advisors, LLC, a wholly owned company of Northwestern Mutual, is an investment adviser to Northwestern Mutual and certain Northwestern Mutual-affiliated entities and may be deemed to be the indirect beneficial owner with shared voting power and investment power with respect to 1,821 shares of our common stock held by Northwestern Mutual Series Fund, Inc./Index 600 Stock Portfolio as of July 11, 2007.

(8)

This selling securityholder is an affiliate of a broker-dealer. Northwestern Mutual has advised us that it is affiliated with the following broker-dealers: Northwestern Mutual Investment Services, LLC, Russell Institutional Services, Russell Implementation Services, Inc., Russell Fund Distributors, Inc., and Todd Securities, L.L.C.

(9)

This selling securityholder has advised us that, as of June 25, 2007, it held a beneficial ownership interest in 21,257 shares of our common stock, not including the shares of our common stock issuable upon conversion of the notes.