Long-term Debt



(in thousands)	March 31, 2013			December 31, 2012
Senior notes - 4.10% due 2022	$	349,422		$	349,407
Revolving credit facility	76,000			75,000
Lines of credit	5,193			4,382
	430,615			428,789
Current maturities of long-term debt	(5,193		)	(4,382		)
	$	425,422		$	424,407

At March 31, 2013, we had outstanding senior notes in the aggregate principal amount of $350 million that bear interest at a fixed rate of 4.10% and are due in 2022 (4.10% senior notes). During March 2013, we registered these 4.10% senior notes under the Securities Act of 1933 and commenced an offer to exchange the previously unregistered 4.10% senior notes that were outstanding at December 31, 2012 for an equal aggregate principal amount.

The following table provides information related to the unused portion of our revolving credit facility in effect at March 31, 2013 and December 31, 2012:



(in millions)	March 31, 2013		December 31, 2012
Maximum borrowing capacity under the revolving credit facility	$	650.0	$	650.0
Outstanding borrowings under the revolving credit facility	76.0		75.0
Outstanding letters of credit	3.1		3.1
Unused portion of revolving credit facility	$	570.9	$	571.9

For further information on the outstanding letters of credit, see Note 8. The average interest rate for borrowings under our revolving credit facility was 2.16% during the first three months of 2013 and 1.84% during 2012.

We were in compliance with all covenants under our debt agreements at March 31, 2013 and at December 31, 2012.