Estimating Useful Life and Percent Used Up The property and equipment footnote from the Deere \& Company Equipment and Operations segment follows. Property and Depreciation A summary of property and equipment at October 31 follows. 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% ) %