pension expense .
considering the years 2015-2016 , what is the decrease observed in the cash contributions to funded plans and benefit payments for unfunded plans?
( a ) effective in 2016 , the company began to measure the service cost and interest cost components of pension expense by applying spot rates along the yield curve to the relevant projected cash flows , as we believe this provides a better measurement of these costs . the company has accounted for this as a change in accounting estimate and , accordingly has accounted for it on a prospective basis . this change does not affect the measurement of the total benefit obligation . 2016 vs . 2015 pension expense , excluding special items , decreased from the prior year due to the adoption of the spot rate approach which reduced service cost and interest cost , the impact from expected return on assets and demographic gains , partially offset by the impact of the adoption of new mortality tables for our major plans . special items of $ 7.3 included pension settlement losses of $ 6.4 , special termination benefits of $ 2.0 , and curtailment gains of $ 1.1 . these resulted primarily from our recent business restructuring and cost reduction actions . 2015 vs . 2014 the decrease in pension expense , excluding special items , was due to the impact from expected return on assets , a 40 bp reduction in the weighted average compensation increase assumption , and lower service cost and interest cost . the decrease was partially offset by the impact of higher amortization of actuarial losses , which resulted primarily from a 60 bp decrease in weighted average discount rate . special items of $ 35.2 included pension settlement losses of $ 21.2 , special termination benefits of $ 8.7 , and curtailment losses of $ 5.3 . these resulted primarily from our recent business restructuring and cost reduction actions . 2017 outlook in 2017 , pension expense , excluding special items , is estimated to be approximately $ 70 to $ 75 , an increase of $ 10 to $ 15 from 2016 , resulting primarily from a decrease in discount rates , offset by favorable asset experience , effects of the versum spin-off and the adoption of new mortality tables . pension settlement losses of $ 10 to $ 15 are expected , dependent on the timing of retirements . in 2017 , we expect pension expense to include approximately $ 164 for amortization of actuarial losses compared to $ 121 in 2016 . net actuarial losses of $ 484 were recognized in accumulated other comprehensive income in 2016 , primarily attributable to lower discount rates and improved mortality projections . actuarial gains/losses are amortized into pension expense over prospective periods to the extent they are not offset by future gains or losses . future changes in the discount rate and actual returns on plan assets different from expected returns would impact the actuarial gains/losses and resulting amortization in years beyond 2017 . during the first quarter of 2017 , the company expects to record a curtailment loss estimated to be $ 5 to $ 10 related to employees transferring to versum . the loss will be reflected in the results from discontinued operations on the consolidated income statements . we continue to evaluate opportunities to manage the liabilities associated with our pension plans . pension funding pension funding includes both contributions to funded plans and benefit payments for unfunded plans , which are primarily non-qualified plans . with respect to funded plans , our funding policy is that contributions , combined with appreciation and earnings , will be sufficient to pay benefits without creating unnecessary surpluses . in addition , we make contributions to satisfy all legal funding requirements while managing our capacity to benefit from tax deductions attributable to plan contributions . with the assistance of third party actuaries , we analyze the liabilities and demographics of each plan , which help guide the level of contributions . during 2016 and 2015 , our cash contributions to funded plans and benefit payments for unfunded plans were $ 79.3 and $ 137.5 , respectively . for 2017 , cash contributions to defined benefit plans are estimated to be $ 65 to $ 85 . the estimate is based on expected contributions to certain international plans and anticipated benefit payments for unfunded plans , which .