concentration of credit risk credit risk represents the accounting loss that would be recognized at the reporting date if counterparties failed to perform as contracted .
the company believes the likelihood of incurring material losses due to concentration of credit risk is remote .
the principal financial instruments subject to credit risk are as follows : cash and cash equivalents - the company maintains cash deposits with major banks , which from time to time may exceed insured limits .
the possibility of loss related to financial condition of major banks has been deemed minimal .
additionally , the company 2019s investment policy limits exposure to concentrations of credit risk and changes in market conditions .
accounts receivable - a large number of customers in diverse industries and geographies , as well as the practice of establishing reasonable credit lines , limits credit risk .
based on historical trends and experiences , the allowance for doubtful accounts is adequate to cover potential credit risk losses .
foreign currency and interest rate contracts and derivatives - exposure to credit risk is limited by internal policies and active monitoring of counterparty risks .
in addition , the company uses a diversified group of major international banks and financial institutions as counterparties .
the company does not anticipate nonperformance by any of these counterparties .
cash and cash equivalents cash equivalents include highly-liquid investments with a maturity of three months or less when purchased .
accounts receivable and allowance for doubtful accounts accounts receivable are carried at their face amounts less an allowance for doubtful accounts .
accounts receivable are recorded at the invoiced amount and generally do not bear interest .
the company estimates the balance of allowance for doubtful accounts by analyzing accounts receivable balances by age and applying historical write-off and collection trend rates .
the company 2019s estimates include separately providing for customer balances based on specific circumstances and credit conditions , and when it is deemed probable that the balance is uncollectible .
account balances are charged off against the allowance when it is determined the receivable will not be recovered .
the company 2019s allowance for doubtful accounts balance also includes an allowance for the expected return of products shipped and credits related to pricing or quantities shipped of $ 15 million as of december 31 , 2015 and 2014 and $ 14 million as of december 31 , 2013 .
returns and credit activity is recorded directly to sales .
the following table summarizes the activity in the allowance for doubtful accounts: .

(millions)
2015
2014
2013
Beginning balance
$77
$81
$73
Bad debt expense
26
23
28
Write-offs
(22)
(20)
(21)
Other (a)
(6)
(7)
1
Ending balance
$75
$77
$81

( a ) other amounts are primarily the effects of changes in currency translations and the impact of allowance for returns and credits .
inventory valuations inventories are valued at the lower of cost or market .
certain u.s .
inventory costs are determined on a last-in , first-out ( lifo ) basis .
lifo inventories represented 39% ( 39 % ) and 37% ( 37 % ) of consolidated inventories as of december 31 , 2015 and 2014 , respectively .
lifo inventories include certain legacy nalco u.s .
inventory acquired at fair value as part of the nalco merger .
all other inventory costs are determined using either the average cost or first-in , first-out ( fifo ) methods .
inventory values at fifo , as shown in note 5 , approximate replacement during the fourth quarter of 2015 , the company improved estimates related to its inventory reserves and product costing , resulting in a net pre-tax charge of approximately $ 6 million .
separately , the actions resulted in charge of $ 20.6 million related to inventory reserve calculations , partially offset by a gain of $ 14.5 million related to the capitalization of certain cost components into inventory .
both of these items are reflected in note 3. .

Question: Analyse this data from a financial earnings document. what is the net change in the balance of allowance for doubtful accounts during 2015?
Choices:
-2.0
10
-50
-49
85
Correct choice index: 0