shutdown .the customer , which primarily received products from the tonnage gases segment , filed for bankruptcy in may 2012 and announced the mill shutdown in august 2012 .pension settlement loss our u.s .supplemental pension plan provides for a lump sum benefit payment option at the time of retirement , or for corporate officers , six months after the retirement date .pension settlements are recognized when cash payments exceed the sum of the service and interest cost components of net periodic pension cost of the plan for the fiscal year .the participant 2019s vested benefit is considered fully settled upon cash payment of the lump sum .we recognized $ 12.4 of settlement charges in 2013 .advisory costs during the fourth quarter of 2013 , we incurred legal and other advisory fees of $ 10.1 ( $ 6.4 after-tax , or $ .03 per share ) in connection with our response to the rapid acquisition of a large position in shares of our common stock by pershing square capital management llc and its affiliates ( pershing square ) .these fees , which are reflected on the consolidated income statements as 201cadvisory costs , 201d include costs incurred before and after pershing square 2019s disclosure of its holdings and cover advisory services related to the adoption of the shareholders rights plan , preparation for a potential proxy solicitation campaign , and entering into an agreement with pershing square .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 .2013 vs .2012 other income ( expense ) , net of $ 70.2 increased $ 23.1 , primarily due to higher gains from the sale of a number of small assets and investments and a favorable commercial contract settlement , partially offset by lower government grants .otherwise , no individual items were significant in comparison to the prior year .2012 vs .2011 other income ( expense ) , net of $ 47.1 increased $ 5.4 , primarily due to favorable foreign exchange and reimbursements from government grants for expense , partially offset by lower gains from the sale of assets .otherwise , no individual items were significant in comparison to the prior year .interest expense .
[['', '2013', '2012', '2011'], ['interest incurred', '$ 167.6', '$ 153.9', '$ 138.2'], ['less : capitalized interest', '25.8', '30.2', '22.7'], ['interest expense', '$ 141.8', '$ 123.7', '$ 115.5']]
2013 vs .2012 interest incurred increased $ 13.7 .the increase was driven primarily by a higher average debt balance for $ 41 , partially offset by a lower average interest rate on the debt portfolio of $ 24 .the change in capitalized interest was driven by a decrease in project spending and a lower average interest rate .2012 vs .2011 interest incurred increased $ 15.7 .the increase was driven primarily by a higher average debt balance and debt issuance costs related to the indura s.a .acquisition , partially offset by the impact of a stronger dollar on the translation of foreign currency interest .the change in capitalized interest was driven by an increase in project spending which qualified for capitalization .effective tax rate the effective tax rate equals the income tax provision divided by income from continuing operations before taxes .refer to note 22 , income taxes , to the consolidated financial statements for details on factors affecting the effective tax rate .2013 vs .2012 on a gaap basis , the effective tax rate was 22.8% ( 22.8 % ) and 21.9% ( 21.9 % ) in 2013 and 2012 , respectively .the current year rate includes income tax benefits of $ 73.7 related to the business restructuring and cost reduction plans and $ 3.7 for the advisory costs .the prior year rate includes income tax benefits of $ 105.0 related to the business restructuring and cost reduction plans , $ 58.3 related to the second quarter spanish tax ruling , and $ 3.7 related to the customer .

Question: considering the gaap basis , what was the growth observed in the effective tax rate during 2012 and 2013?
Answer: 0.9%
Explanation: it is the variation between these effective tax rates during 2012 and 2013 .