what percentage of total material obligations and commitments as of december 31 , 2011 are operating leases?
the railroad collected approximately $ 18.8 billion and $ 16.3 billion of receivables during the years ended december 31 , 2011 and 2010 , respectively . upri used certain of these proceeds to purchase new receivables under the facility . the costs of the receivables securitization facility include interest , which will vary based on prevailing commercial paper rates , program fees paid to banks , commercial paper issuing costs , and fees for unused commitment availability . the costs of the receivables securitization facility are included in interest expense and were $ 4 million and $ 6 million for 2011 and 2010 , respectively . prior to adoption of the new accounting standard , the costs of the receivables securitization facility were included in other income and were $ 9 million for 2009 . the investors have no recourse to the railroad 2019s other assets , except for customary warranty and indemnity claims . creditors of the railroad do not have recourse to the assets of upri . in august 2011 , the receivables securitization facility was renewed for an additional 364-day period at comparable terms and conditions . contractual obligations and commercial commitments as described in the notes to the consolidated financial statements and as referenced in the tables below , we have contractual obligations and commercial commitments that may affect our financial condition . based on our assessment of the underlying provisions and circumstances of our contractual obligations and commercial commitments , including material sources of off-balance sheet and structured finance arrangements , other than the risks that we and other similarly situated companies face with respect to the condition of the capital markets ( as described in item 1a of part ii of this report ) , there is no known trend , demand , commitment , event , or uncertainty that is reasonably likely to occur that would have a material adverse effect on our consolidated results of operations , financial condition , or liquidity . in addition , our commercial obligations , financings , and commitments are customary transactions that are similar to those of other comparable corporations , particularly within the transportation industry . the following tables identify material obligations and commitments as of december 31 , 2011 : payments due by december 31 , contractual obligations after millions total 2012 2013 2014 2015 2016 2016 other .

|  |  | <i>Payments Due by December 31,</i> |
| :--- | :--- | :--- |
| <i>Contractual Obligations</i><i>Millions</i> | <i>Total</i> | <i>2012</i> | <i>2013</i> | <i>2014</i> | <i>2015</i> | <i>2016</i> | <i>After 2016</i> | <i>Other</i> |
| Debt [a] | $12,516 | $538 | $852 | $887 | $615 | $652 | $8,972 | $- |
| Operating leases [b] | 4,528 | 525 | 489 | 415 | 372 | 347 | 2,380 | - |
| Capital lease obligations [c] | 2,559 | 297 | 269 | 276 | 276 | 262 | 1,179 | - |
| Purchase obligations [d] | 5,137 | 2,598 | 568 | 560 | 276 | 245 | 858 | 32 |
| Other post retirement benefits [e] | 249 | 26 | 26 | 26 | 26 | 26 | 119 | - |
| Income tax contingencies [f] | 107 | 31 | - | - | - | - | - | 76 |
| Total contractualobligations | $25,096 | $4,015 | $2,204 | $2,164 | $1,565 | $1,532 | $13,508 | $108 |

[a] excludes capital lease obligations of $ 1874 million and unamortized discount of $ 364 million . includes an interest component of $ 5120 million . [b] includes leases for locomotives , freight cars , other equipment , and real estate . [c] represents total obligations , including interest component of $ 685 million . [d] purchase obligations include locomotive maintenance contracts ; purchase commitments for fuel purchases , locomotives , ties , ballast , and rail ; and agreements to purchase other goods and services . for amounts where we cannot reasonably estimate the year of settlement , they are reflected in the other column . [e] includes estimated other post retirement , medical , and life insurance payments and payments made under the unfunded pension plan for the next ten years . no amounts are included for funded pension obligations as no contributions are currently required . [f] future cash flows for income tax contingencies reflect the recorded liability for unrecognized tax benefits , including interest and penalties , as of december 31 , 2011 . where we can reasonably estimate the years in which these liabilities may be settled , this is shown in the table . for amounts where we cannot reasonably estimate the year of settlement , they are reflected in the other column. .

leases_2011 = 4528
total_obligations = 25096
percent_leases = leases_2011 / total_obligations
answer = percent_leases * 100