the components of external long-term debt were as follows : ( in millions ) 2017 2016 .
what was the percentage growth in the total long-term debt from 2016 to 2017
senior notes payments during the next five years as of december 31 , 2017 are zero in 2018 through 2019 , $ 400 million in 2020 and zero in 2021 through 2022 . in our debt agreements , there are normal and customary events of default which would permit the lenders to accelerate the debt if not cured within applicable grace periods , such as failure to pay principal or interest when due or a change in control of the company . there were no events of default as of december 31 , 2017 . 9 . financial instruments we do not enter into financial instruments for trading or speculative purposes . we principally use financial instruments to reduce the impact of changes in foreign currency exchange rates and commodities used as raw materials in our products . the principal derivative financial instruments we enter into on a routine basis are foreign exchange contracts . derivative financial instruments are recorded at fair value . the counterparties to derivative contracts are major financial institutions . we are subject to credit risk on these contracts equal to the fair value of these instruments . management currently believes that the risk of incurring material losses is unlikely and that the losses , if any , would be immaterial to the company . raw materials used by the company are subject to price volatility caused by weather , supply conditions , geopolitical and economic variables , and other unpredictable external factors . as a result , from time to time , we enter into commodity swaps to manage the price risk associated with forecasted purchases of materials used in our operations . we account for these commodity derivatives as economic hedges or cash flow hedges . changes in the fair value of economic hedges are recorded directly into current period earnings . there were no material commodity swap contracts outstanding for the years ended december 31 , 2017 and 2016 . we enter into foreign exchange contracts primarily to hedge forecasted sales and purchases denominated in select foreign currencies , thereby limiting currency risk that would otherwise result from changes in exchange rates . the periods of the foreign exchange contracts correspond to the periods of the forecasted transactions , which generally do not exceed 12 to 15 months subsequent to the latest balance sheet date . for derivative instruments that are designated as fair value hedges , the gain or loss on the derivative instrument , as well as the offsetting loss or gain on the hedged item , are recognized on the same line of the statement of income . the effective portions of cash flow hedges are reported in other comprehensive income ( 201coci 201d ) and are recognized in the statement of income when the hedged item affects earnings . the changes in fair value for net investment hedges are recognized in the statement of income when realized upon sale or upon complete or substantially complete liquidation of the investment in the foreign entity . the ineffective portion of all hedges is recognized in current period earnings . in addition , changes in the fair value of all economic hedge transactions are immediately recognized in current period earnings . our primary foreign currency hedge contracts pertain to the canadian dollar , the british pound , and the mexican peso . the gross u.s . dollar equivalent notional amount of all foreign currency derivative hedges outstanding at december 31 , 2017 was $ 282.8 million , representing a net settlement liability of $ 4.8 million . based on foreign exchange rates as of december 31 , 2017 , we estimate that $ 3.0 million of net foreign currency .