.0% ( 6.0 % ) . the average annual actual return on the plan assets over the past 10 and 25 years has been 7.8% ( 7.8 % ) and 10.0% ( 10.0 % ) , respectively . return on assets assumptions for international pension and other post-retirement benefit plans are calculated on a plan-by-plan basis using plan asset allocations and expected long-term rate of return assumptions . during 2015 , the company contributed $ 264 million to its u.s