Total property and equipment additions in 2015, 2014 and 2013 were $666 million, $1,016 million and \$1,158 million, and depreciation was \$692 million, \$696 million and $637 million, respectively. a. Compute the average useful life of Deere's depreciable assets at year-end 2015. Round answer to one decimal place. x years b. Estimate the percent used up of Deere's depreciable assets at year-end 2015. Round answer to one decimal place (ex: 0.2345=23.5%) %