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: Analyse this data from a financial earnings document. considering the gaap basis , what was the growth observed in the effective tax rate during 2012 and 2013?
Choices:
0
1.041
13.481
9000
0.009
Correct choice index: 4