8. DEBT AND CAPITAL LEASE OBLIGATIONS 9. INCOME TAXES Debt at December 31, 2013 and 2012 is summarized in the following table (in thousands): In 2011, we issued two series of senior notes with an aggregate principal amount of $150 million (“Senior Notes”) in a private place- ment transaction. Series A consists of $75 million in aggregate principal amount of notes that bear interest at a fixed rate of 4.01%  and are due in full on September 30, 2021. Series B consists of $75 million in aggregate principal amount of notes that bear interest  at a fixed rate of 4.11% and are due in full on September 30, 2023. Interest on each series of the Senior Notes is payable semi-annu- ally on March 30 and September 30. We maintain a revolving credit facility (the “Credit Facility”) with an aggregate borrowing capacity of $300 million at December 31,  2013. The Credit Facility provides an option to increase the commitment under the Credit Facility to $350 million, if certain conditions  are met. The Credit Facility bears interest at variable rates from LIBOR plus 1.50% to a maximum of LIBOR plus 2.25%. Any outstand- ing balance under the Credit Facility is due September 28, 2016 when the Credit Facility matures. Interest payment terms are variable  depending upon the specific type of borrowing under this facility. Our available capacity at any point in time is reduced by borrowings  outstanding at the time and outstanding letters of credit which totaled $19.1 million at December 31, 2013, resulting in an available  borrowing capacity under the Credit Facility of $163.9 million. In addition to those items under the Credit Facility, we had $22.3 million  of outstanding letters of credit and performance guarantees and bonds from other sources at December 31, 2013. The terms of the Credit Facility and Senior Notes require us to meet certain covenants, including, but not limited to, certain minimum  equity and cash flow ratios. We believe that we are in compliance with all such covenants contained in our credit agreements. Certain  of our material, wholly-owned subsidiaries are guarantors or co-borrowers under the Credit Facility and Senior Notes. The estimated fair value of total debt at December 31, 2013 and 2012 approximated the book value of total debt. The fair value was  estimated using Level 2 inputs by calculating the sum of the discounted future interest and principal payments through the date of  maturity. The components of income before income tax expense for 2013, 2012 and 2011 are as follows (in thousands): 47 December 31, 2013 December 31, 2012 Senior Notes $ 150,000 $ 150,000 Credit Facility 117,000 84,000 Capital lease obligations 28 73 Total debt 267,028 234,073 Less - current maturities of long-term debt and capital lease obligations 26 40  Long-term debt and capital lease obligations, net $ 267,002 $ 234,033 2013 2012 2011 United States $ 150,023 $ 135,992 $ 115,413 Other countries 174,079 152,468 123,429 Income before income tax expense $ 324,102 $ 288,460 $ 238,842