addition , fuel costs were lower as gross-ton miles decreased 9% ( 9 % ) . the fuel consumption rate ( c-rate ) , computed as gallons of fuel consumed divided by gross ton-miles in thousands , increased 1% ( 1 % ) compared to 2014 . decreases in heavier , more fuel-efficient shipments , decreased gross-ton miles and increased the c-rate . volume growth of 7% ( 7 % ) , as measured by gross ton-miles , drove the increase in fuel expense in 2014 compared to 2013 . this was essentially offset by lower locomotive diesel fuel prices , which averaged $ 2.97 per gallon ( including taxes and transportation costs ) in 2014 , compared to $ 3.15 in 2013 , along with a slight improvement in c-rate , computed as gallons of fuel consumed divided by gross ton-miles . depreciation 2013 the majority of depreciation relates to road property , including rail , ties , ballast , and other track material . a higher depreciable asset base , reflecting higher capital spending in recent years , increased depreciation expense in 2015 compared to 2014 . this increase was partially offset by our recent depreciation studies that resulted in lower depreciation rates for some asset classes . depreciation was up 7% ( 7 % ) in 2014 compared to 2013 . a higher depreciable asset base , reflecting higher ongoing capital spending drove the increase . equipment and other rents 2013 equipment and other rents expense primarily includes rental expense that the railroad pays for freight cars owned by other railroads or private companies ; freight car , intermodal , and locomotive leases ; and office and other rent expenses . equipment and other rents expense decreased $ 4 million compared to 2014 primarily from a decrease in manifest and intermodal shipments , partially offset by growth in finished vehicle shipments . higher intermodal volumes and longer cycle times increased short-term freight car rental expense in 2014 compared to 2013 . lower equipment leases essentially offset the higher freight car rental expense , as we exercised purchase options on some of our leased equipment . other 2013 other expenses include state and local taxes , freight , equipment and property damage , utilities , insurance , personal injury , environmental , employee travel , telephone and cellular , computer software , bad debt , and other general expenses . other expenses were flat in 2015 compared to 2014 as higher property taxes were offset by lower costs in other areas . higher property taxes , personal injury expense and utilities costs partially offset by lower environmental expense and costs associated with damaged freight resulted in an increase in other costs in 2014 compared to 2013 . non-operating items % (  % ) change % (  % ) change millions 2015 2014 2013 2015 v 2014 2014 v 2013 .
what was the change in millions in other income from 2014 to 2015?
other income 2013 other income increased in 2015 compared to 2014 primarily due to a $ 113 million gain from a real estate sale in the second quarter of 2015 , partially offset by a gain from the sale of a permanent easement in 2014 . other income increased in 2014 versus 2013 due to higher gains from real estate sales and a sale of a permanent easement . these gains were partially offset by higher environmental costs on non-operating property in 2014 and lower lease income due to the $ 17 million settlement of a land lease contract in interest expense 2013 interest expense increased in 2015 compared to 2014 due to an increased weighted- average debt level of $ 13.0 billion in 2015 from $ 10.7 billion in 2014 , partially offset by the impact of a lower effective interest rate of 4.8% ( 4.8 % ) in 2015 compared to 5.3% ( 5.3 % ) in 2014 . interest expense increased in 2014 versus 2013 due to an increased weighted-average debt level of $ 10.7 billion in 2014 from $ 9.6 billion in 2013 , which more than offset the impact of the lower effective interest rate of 5.3% ( 5.3 % ) in 2014 versus 5.7% ( 5.7 % ) in 2013. .