contractual obligations we summarize our enforceable and legally binding contractual obligations at september 30 , 2018 , and the effect these obligations are expected to have on our liquidity and cash flow in future periods in the following table . certain amounts in this table are based on management fffds estimates and assumptions about these obligations , including their duration , the possibility of renewal , anticipated actions by third parties and other factors , including estimated minimum pension plan contributions and estimated benefit payments related to postretirement obligations , supplemental retirement plans and deferred compensation plans . because these estimates and assumptions are subjective , the enforceable and legally binding obligations we actually pay in future periods may vary from those presented in the table. .
what percent of payments are differed until after 2023?
( 1 ) includes only principal payments owed on our debt assuming that all of our long-term debt will be held to maturity , excluding scheduled payments . we have excluded $ 205.2 million of fair value of debt step-up , deferred financing costs and unamortized bond discounts from the table to arrive at actual debt obligations . see fffdnote 13 . debt fffd fffd of the notes to consolidated financial statements for information on the interest rates that apply to our various debt instruments . ( 2 ) see fffdnote 14 . operating leases fffd of the notes to consolidated financial statements for additional information . ( 3 ) the fair value step-up of $ 18.5 million is excluded . see fffdnote 13 . debt fffd fffd capital lease and other indebtednesstt fffd of the notes to consolidated financial statements for additional information . ( 4 ) purchase obligations include agreements to purchase goods or services that are enforceable and legally binding and that specify all significant terms , including : fixed or minimum quantities to be purchased ; fixed , minimum or variable price provision ; and the approximate timing of the transaction . purchase obligations exclude agreements that are cancelable without penalty . ( 5 ) we have included in the table future estimated minimum pension plan contributions and estimated benefit payments related to postretirement obligations , supplemental retirement plans and deferred compensation plans . our estimates are based on factors , such as discount rates and expected returns on plan assets . future contributions are subject to changes in our underfunded status based on factors such as investment performance , discount rates , returns on plan assets and changes in legislation . it is possible that our assumptions may change , actual market performance may vary or we may decide to contribute different amounts . we have excluded $ 247.8 million of multiemployer pension plan withdrawal liabilities recorded as of september 30 , 2018 due to lack of definite payout terms for certain of the obligations . see fffdnote 4 . retirement plans fffd multiemployer plans fffd of the notes to consolidated financial statements for additional information . ( 6 ) we have not included the following items in the table : fffd an item labeled fffdother long-term liabilities fffd reflected on our consolidated balance sheet because these liabilities do not have a definite pay-out scheme . fffd $ 158.4 million from the line item fffdpurchase obligations and other fffd for certain provisions of the financial accounting standards board fffds ( fffdfasb fffd ) accounting standards codification ( fffdasc fffd ) 740 , fffdincome taxes fffd associated with liabilities for uncertain tax positions due to the uncertainty as to the amount and timing of payment , if any . in addition to the enforceable and legally binding obligations presented in the table above , we have other obligations for goods and services and raw materials entered into in the normal course of business . these contracts , however , are subject to change based on our business decisions . expenditures for environmental compliance see item 1 . fffdbusiness fffd fffd governmental regulation fffd environmental and other matters fffd , fffdbusiness fffd fffd governmental regulation fffd cercla and other remediation costs fffd , and fffd fffdbusiness fffd fffd governmental regulation fffd climate change fffd for a discussion of our expenditures for environmental compliance. .