Debt

Total debt at June 30, 2017 and December 31, 2016 consisted of the following:



	Interest rate	June 30, 2017		December 31, 2016
Notes due September 2017	5.75%	$	385,109	$	385,109
Notes due March 2018	5.6%	250,000		250,000
Notes due May 2018	4.75%	350,000		350,000
Notes due March 2019	6.25%	300,000		300,000
Notes due October 2021	3.375%	600,000		600,000
Notes due May 2022	3.875%	400,000		—
Notes due March 2024	4.625%	500,000		500,000
Notes due January 2037	5.25%	35,841		115,041
Notes due March 2043	6.7%	425,000		425,000
Term loans	Variable	300,000		450,000
Other debt		5,552		5,677
Principal amount		3,551,502		3,380,827
Less: unamortized debt discount and issuance costs		30,630		28,796
Plus: unamortized interest rate swap proceeds		7,895		12,859
Total debt		3,528,767		3,364,890
Less: current portion long-term debt		985,291		614,485
Long-term debt		$	2,543,476	$	2,750,405

In May 2017, we issued $400 million of 3.875% fixed rate notes. Interest is payable semi-annually, commencing November 15, 2017 and is subject to adjustment from time to time if either Moody's or S&P (or a substitute ratings agency) downgrades (or downgrades and subsequently upgrades) the credit rating assigned to the notes. The notes mature in May 2022, but may be redeemed, at our option, in whole or in part, at any time or from time to time at par plus accrued, unpaid interest and a make-whole amount, if any. The proceeds were used to repay the $150 million term loan due in June 2017 and the remainder, together with cash on hand and other financing options, will be used to repay a portion of the $385 million notes due September 2017.

In January 2017, bondholders of the 5.25% Notes due 2037 caused us to redeem $79 million of the debt outstanding.