Sandra L. Helton
Director

Sandra L. Helton, 61, was Executive Vice President and Chief Financial Officer of Telephone & Data Systems, Inc., a telecommunications service company, (“TDS”) from October 2000 through December 2006. She joined TDS as Executive Vice President—Finance and Chief Financial Officer in August 1998. Prior to joining TDS, Ms. Helton was the Vice President and Corporate Controller of Compaq Computer Corporation between 1997 and 1998. Prior to that time, Ms. Helton was employed by Corning Incorporated. At Corning, Ms. Helton was Senior Vice President and Treasurer between 1994 and 1997 and was Vice President and Treasurer between 1991 and 1994. Ms. Helton has been a member of the Covance Board since September 2003. Ms. Helton is also a Director of The Principal Financial Group, a global financial institution, and was elected a Director of Lexmark International, Inc., a printing and imaging solutions company, on February 24, 2011. Ms. Helton was a Director of TDS and US Cellular Corporation through December 31, 2006.