.0 billion . interest on borrowings outstanding accrues at a rate based on the applicable london interbank offered rate plus a spread . the 2017 credit facility requires the company not to exceed a maximum leverage ratio ( ratio of net debt to earnings before interest , taxes , depreciation and amortization , where net debt equals total debt less unrestricted cash ) of 3 to 1 , which was satisfied with a ratio of less than 1 to 1 at december 31 , 2017