the following table summarizes our future estimated cash payments under existing contractual obligations , including payments due by period: .
what was the percentage change of our accrued trade liabilities in 2019 compared to 2018
( a ) amounts represent the expected cash payments of our long-term debt and do not include $ 0.3 million for capital leases or $ 72.0 million for net unamortized debt issuance costs , premiums and discounts , and fair value adjustments . ( b ) operating leases represents the minimum rental commitments under non-cancelable operating leases . ( c ) the majority of the purchase obligations represent commitments for raw material and packaging to be utilized in the normal course of business and for consumer marketing spending commitments that support our brands . for purposes of this table , arrangements are considered purchase obligations if a contract specifies all significant terms , including fixed or minimum quantities to be purchased , a pricing structure , and approximate timing of the transaction . most arrangements are cancelable without a significant penalty and with short notice ( usually 30 days ) . any amounts reflected on the consolidated balance sheets as accounts payable and accrued liabilities are excluded from the table above . ( d ) the fair value of our foreign exchange , equity , commodity , and grain derivative contracts with a payable position to the counterparty was $ 17.3 million as of may 26 , 2019 , based on fair market values as of that date . future changes in market values will impact the amount of cash ultimately paid or received to settle those instruments in the future . other long-term obligations mainly consist of liabilities for accrued compensation and benefits , including the underfunded status of certain of our defined benefit pension , other postretirement benefit , and postemployment benefit plans , and miscellaneous liabilities . we expect to pay approximately $ 20 million of benefits from our unfunded postemployment benefit plans and approximately $ 18 million of deferred compensation in fiscal 2020 . we are unable to reliably estimate the amount of these payments beyond fiscal 2020 . as of may 26 , 2019 , our total liability for uncertain tax positions and accrued interest and penalties was $ 165.1 million . significant accounting estimates for a complete description of our significant accounting policies , please see note 2 to the consolidated financial statements in item 8 of this report . our significant accounting estimates are those that have a meaningful impact on the reporting of our financial condition and results of operations . these estimates include our accounting for promotional expenditures , valuation of long-lived assets , intangible assets , redeemable interest , stock-based compensation , income taxes , and defined benefit pension , other postretirement benefit , and postemployment benefit plans . revenue recognition our revenues are reported net of variable consideration and consideration payable to our customers , including trade promotion , consumer coupon redemption and other costs , including estimated allowances for returns , unsalable product , and prompt pay discounts . trade promotions are recorded using significant judgment of estimated participation and performance levels for offered programs at the time of sale . differences between estimated expenses and actual costs are recognized as a change in management estimate in a subsequent period . our accrued trade liabilities were $ 484 million as of may 26 , 2019 , and $ 500 million as of may 27 , 2018 . because these amounts are significant , if our estimates are inaccurate we would have to make adjustments in subsequent periods that could have a significant effect on our results of operations. .