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. Useful Lives* (Years) Property and Equipment ($ millions) Land 23 11 8 2015 2014 $114 $120 3,460 3,037 5,499 5,089 1,567 1,552 875 889 345 530 11,860 11,217 5,846 5,694 $6,014 $5,523 Buildings and building equipment Machinery and equipment Dies, patterns, tools, etc All other Construction in progress Total at cost Less accumulated depreciation Total *Weighted averages 5 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. 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%) %