gain on previously held equity interest on 30 december 2014 , we acquired our partner 2019s equity ownership interest in a liquefied atmospheric industrial gases production joint venture in north america for $ 22.6 , which increased our ownership from 50% ( 50 % ) to 100% ( 100 % ) . the transaction was accounted for as a business combination , and subsequent to the acquisition , the results were consolidated within our industrial gases 2013 americas segment . we recorded a gain of $ 17.9 ( $ 11.2 after-tax , or $ .05 per share ) as a result of revaluing our previously held equity interest to fair value as of the acquisition date . refer to note 6 , business combination , to the consolidated financial statements for additional details . other income ( expense ) , net items recorded to other income ( expense ) , net arise from transactions and events not directly related to our principal income earning activities . the detail of other income ( expense ) , net is presented in note 23 , supplemental information , to the consolidated financial statements . 2017 vs . 2016 other income ( expense ) , net of $ 121.0 increased $ 71.6 , primarily due to income from transition services agreements with versum and evonik , income from the sale of assets and investments , including a gain of $ 12.2 ( $ 7.6 after-tax , or $ .03 per share ) resulting from the sale of a parcel of land , and a favorable foreign exchange impact . 2016 vs . 2015 other income ( expense ) , net of $ 49.4 increased $ 3.9 , primarily due to lower foreign exchange losses , favorable contract settlements , and receipt of a government subsidy . fiscal year 2015 included a gain of $ 33.6 ( $ 28.3 after tax , or $ .13 per share ) resulting from the sale of two parcels of land . no other individual items were significant in comparison to fiscal year 2015 . interest expense .
considering the years 2015-2017 , what is the average interest expense?
2017 vs . 2016 interest incurred decreased $ 8.3 as the impact from a lower average debt balance of $ 26 was partially offset by the impact from a higher average interest rate on the debt portfolio of $ 19 . the change in capitalized interest was driven by a decrease in the carrying value of projects under construction , primarily as a result of our decision to exit from the energy-from-waste business . 2016 vs . 2015 interest incurred decreased $ 4.0 . the decrease primarily resulted from a stronger u.s . dollar on the translation of foreign currency interest of $ 6 , partially offset by a higher average debt balance of $ 2 . the change in capitalized interest was driven by a decrease in the carrying value of projects under construction , primarily as a result of our exit from the energy-from-waste business . other non-operating income ( expense ) , net other non-operating income ( expense ) , net of $ 29.0 in fiscal year 2017 primarily resulted from interest income on cash and time deposits , which are comprised primarily of proceeds from the sale of pmd . interest income was included in "other income ( expense ) , net" in 2016 and 2015 . interest income in previous periods was not material . loss on extinguishment of debt on 30 september 2016 , in anticipation of the spin-off of emd , versum issued $ 425.0 of notes to air products , who then exchanged these notes with certain financial institutions for $ 418.3 of air products 2019 outstanding commercial paper . this noncash exchange , which was excluded from the consolidated statements of cash flows , resulted in a loss of $ 6.9 ( $ 4.3 after-tax , or $ .02 per share ) . in september 2015 , we made a payment of $ 146.6 to redeem 3000000 unidades de fomento ( 201cuf 201d ) series e 6.30% ( 6.30 % ) bonds due 22 january 2030 that had a carrying value of $ 130.0 and resulted in a net loss of $ 16.6 ( $ 14.2 after-tax , or $ .07 per share ) . .