the net decrease in the 2016 effective tax rate was due , in part , to the 2016 asset impairments in the u.s . and to the current year benefit related to a restructuring of one of our brazilian businesses that increases tax basis in long-term assets . further , the 2015 rate was impacted by the items described below . see note 20 2014asset impairment expense for additional information regarding the 2016 u.s . asset impairments . income tax expense increased $ 101 million , or 27% ( 27 % ) , to $ 472 million in 2015 . the company's effective tax rates were 41% ( 41 % ) and 26% ( 26 % ) for the years ended december 31 , 2015 and 2014 , respectively . the net increase in the 2015 effective tax rate was due , in part , to the nondeductible 2015 impairment of goodwill at our u.s . utility , dp&l and chilean withholding taxes offset by the release of valuation allowance at certain of our businesses in brazil , vietnam and the u.s . further , the 2014 rate was impacted by the sale of approximately 45% ( 45 % ) of the company 2019s interest in masin aes pte ltd. , which owns the company 2019s business interests in the philippines and the 2014 sale of the company 2019s interests in four u.k . wind operating projects . neither of these transactions gave rise to income tax expense . see note 15 2014equity for additional information regarding the sale of approximately 45% ( 45 % ) of the company 2019s interest in masin-aes pte ltd . see note 23 2014dispositions for additional information regarding the sale of the company 2019s interests in four u.k . wind operating projects . our effective tax rate reflects the tax effect of significant operations outside the u.s. , which are generally taxed at rates lower than the u.s . statutory rate of 35% ( 35 % ) . a future proportionate change in the composition of income before income taxes from foreign and domestic tax jurisdictions could impact our periodic effective tax rate . the company also benefits from reduced tax rates in certain countries as a result of satisfying specific commitments regarding employment and capital investment . see note 21 2014income taxes for additional information regarding these reduced rates . foreign currency transaction gains ( losses ) foreign currency transaction gains ( losses ) in millions were as follows: .

2016: aes corporation: -50
chile: -9
colombia: -8
mexico: -8
philippines: 12
united kingdom: 13
argentina: 37
other: -2
total ( 1 ): -15
2015: aes corporation: -31
chile: -18
colombia: 29
mexico: -6
philippines: 8
united kingdom: 11
argentina: 124
other: -10
total ( 1 ): 107
2014: aes corporation: -34
chile: -30
colombia: 17
mexico: -14
philippines: 11
united kingdom: 12
argentina: 66
other: -17
total ( 1 ): 11

total ( 1 ) $ ( 15 ) $ 107 $ 11 _____________________________ ( 1 ) includes gains of $ 17 million , $ 247 million and $ 172 million on foreign currency derivative contracts for the years ended december 31 , 2016 , 2015 and 2014 , respectively . the company recognized a net foreign currency transaction loss of $ 15 million for the year ended december 31 , 2016 primarily due to losses of $ 50 million at the aes corporation mainly due to remeasurement losses on intercompany notes , and losses on swaps and options . this loss was partially offset by gains of $ 37 million in argentina , mainly due to the favorable impact of foreign currency derivatives related to government receivables . the company recognized a net foreign currency transaction gain of $ 107 million for the year ended december 31 , 2015 primarily due to gains of : 2022 $ 124 million in argentina , due to the favorable impact from foreign currency derivatives related to government receivables , partially offset by losses from the devaluation of the argentine peso associated with u.s . dollar denominated debt , and losses at termoandes ( a u.s . dollar functional currency subsidiary ) primarily associated with cash and accounts receivable balances in local currency , 2022 $ 29 million in colombia , mainly due to the depreciation of the colombian peso , positively impacting chivor ( a u.s . dollar functional currency subsidiary ) due to liabilities denominated in colombian pesos , 2022 $ 11 million in the united kingdom , mainly due to the depreciation of the pound sterling , resulting in gains at ballylumford holdings ( a u.s . dollar functional currency subsidiary ) associated with intercompany notes payable denominated in pound sterling , and .

Questions:
what was the effective tax rate in 2015?
and in 2014?
so what was the change between these years?
and the average during this time?

Answers:
41
26
67.0
33.5