EXHIBIT 4

The Reporting Persons engaged in the following transactions in shares of Common Stock of the Company during the past 60 days.  All transactions involved purchases of shares on the Nasdaq National Market System.  The price set forth for each day is the average price per share paid or received by the Reporting Persons for the applicable shares of Common Stock on such day.

Date

 

Type

 

Price

 

Shares

 

3/13/2007

 

Sale

 

7.2047

 

55,000

 

 

 

 

 

 

 

 

 

3/14/2007

 

Sale

 

7.25

 

328

 

 

 

 

 

 

 

 

 

3/15/2007

 

Sale

 

7.25

 

1,400

 

 

 

 

 

 

 

 

 

3/16/2007

 

Sale

 

7.45

 

103,272

 

 

 

 

 

 

 

 

 

3/20/2007

 

Sale

 

7.5030

 

8,000

 

 

 

 

 

 

 

 

 

3/21/2007

 

Sale

 

7.5516

 

4,593

 

 

 

 

 

 

 

 

 

3/22/2007

 

Sale

 

7.5867

 

9,307

 

 

 

 

 

 

 

 

 

3/26/2007

 

Sale

 

7.5525

 

6,100

 

 

 

 

 

 

 

 

 

3/27/2007

 

Sale

 

7.6018

 

1,206

 

 

 

 

 

 

 

 

 

3/28/2007

 

Sale

 

7.5547

 

564

 

 

 

 

 

 

 

 

 

3/29/2007

 

Sale

 

7.5182

 

4,230