pre_text: 2015 vs . 2014 on a gaap basis , the effective tax rate was 24.0% ( 24.0 % ) and 27.1% ( 27.1 % ) in 2015 and 2014 , respectively . the effective tax rate was higher in fiscal year 2014 primarily due to the goodwill impairment charge of $ 305.2 , which was not deductible for tax purposes , and the chilean tax reform enacted in september 2014 which increased income tax expense by $ 20.6 . these impacts were partially offset by an income tax benefit of $ 51.6 associated with losses from transactions and a tax election in a non-u.s . subsidiary . refer to note 10 , goodwill , and note 23 , income taxes , to the consolidated financial statements for additional information . on a non-gaap basis , the effective tax rate was 24.2% ( 24.2 % ) and 24.1% ( 24.1 % ) in 2015 and 2014 , respectively . discontinued operations on 29 march 2016 , the board of directors approved the company 2019s exit of its energy-from-waste ( efw ) business . as a result , efforts to start up and operate its two efw projects located in tees valley , united kingdom , have been discontinued . the decision to exit the business and stop development of the projects was based on continued difficulties encountered and the company 2019s conclusion , based on testing and analysis completed during the second quarter of fiscal year 2016 , that significant additional time and resources would be required to make the projects operational . in addition , the decision allows the company to execute its strategy of focusing resources on its core industrial gases business . the efw segment has been presented as a discontinued operation . prior year efw business segment information has been reclassified to conform to current year presentation . in fiscal 2016 , our loss from discontinued operations , net of tax , of $ 884.2 primarily resulted from the write down of assets to their estimated net realizable value and to record a liability for plant disposition and other costs . income tax benefits related only to one of the projects , as the other did not qualify for a local tax deduction . the loss from discontinued operations also includes land lease costs , commercial and administrative costs , and costs incurred for ongoing project exit activities . we expect additional exit costs of $ 50 to $ 100 to be recorded in future periods . in fiscal 2015 , our loss from discontinued operations , net of tax , related to efw was $ 6.8 . this resulted from costs for land leases and commercial and administrative expenses . in fiscal 2014 , our loss from discontinued operations , net of tax , was $ 2.9 . this included a loss , net of tax , of $ 7.5 for the cost of efw land leases and commercial and administrative expenses . this loss was partially offset by a gain of $ 3.9 for the sale of the remaining homecare business and settlement of contingencies related to a sale of a separate portion of the business to the linde group in 2012 . refer to note 4 , discontinued operations , for additional details . segment analysis industrial gases 2013 americas .
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table: 2016 2015 2014
table: Sales $3,343.6 $3,693.9 $4,078.5
table: Operating income 895.2 808.4 762.6
table: Operating margin 26.8% 21.9% 18.7%
table: Equity affiliates’ income 52.7 64.6 60.9
table: Adjusted EBITDA 1,390.4 1,289.9 1,237.9
table: Adjusted EBITDA margin 41.6% 34.9% 30.4%
question: Analyse this data from a financial earnings document. what is the increase in the operating margin observed in 2015 and 2016?