republic services , inc . notes to consolidated financial statements 2014 ( continued ) credit exposure , we continually monitor the credit worthiness of the financial institutions where we have deposits . concentrations of credit risk with respect to trade accounts receivable are limited due to the wide variety of customers and markets in which we provide services , as well as the dispersion of our operations across many geographic areas . we provide services to commercial , industrial , municipal and residential customers in the united states and puerto rico . we perform ongoing credit evaluations of our customers , but generally do not require collateral to support customer receivables . we establish an allowance for doubtful accounts based on various factors including the credit risk of specific customers , age of receivables outstanding , historical trends , economic conditions and other information . accounts receivable , net of allowance for doubtful accounts accounts receivable represent receivables from customers for collection , transfer , recycling , disposal and other services . our receivables are recorded when billed or when the related revenue is earned , if earlier , and represent claims against third parties that will be settled in cash . the carrying value of our receivables , net of the allowance for doubtful accounts , represents their estimated net realizable value . provisions for doubtful accounts are evaluated on a monthly basis and are recorded based on our historical collection experience , the age of the receivables , specific customer information and economic conditions . we also review outstanding balances on an account-specific basis . in general , reserves are provided for accounts receivable in excess of 90 days outstanding . past due receivable balances are written-off when our collection efforts have been unsuccessful in collecting amounts due . the following table reflects the activity in our allowance for doubtful accounts for the years ended december 31 , 2013 , 2012 and 2011: .

Table:
 | 2013 | 2012 | 2011
balance at beginning of year | $ 45.3 | $ 48.1 | $ 50.9
additions charged to expense | 16.1 | 29.7 | 21.0
accounts written-off | -23.1 ( 23.1 ) | -32.5 ( 32.5 ) | -23.8 ( 23.8 )
balance at end of year | $ 38.3 | $ 45.3 | $ 48.1
restricted cash and marketable securities as of december 31 , 2013 , we had $ 169.7 million of restricted cash and marketable securities .
we obtain funds through the issuance of tax-exempt bonds for the purpose of financing qualifying expenditures at our landfills , transfer stations , collection and recycling centers .
the funds are deposited directly into trust accounts by the bonding authorities at the time of issuance .
as the use of these funds is contractually restricted , and we do not have the ability to use these funds for general operating purposes , they are classified as restricted cash and marketable securities in our consolidated balance sheets .
in the normal course of business , we may be required to provide financial assurance to governmental agencies and a variety of other entities in connection with municipal residential collection contracts , closure or post- closure of landfills , environmental remediation , environmental permits , and business licenses and permits as a financial guarantee of our performance .
at several of our landfills , we satisfy financial assurance requirements by depositing cash into restricted trust funds or escrow accounts .
property and equipment we record property and equipment at cost .
expenditures for major additions and improvements to facilities are capitalized , while maintenance and repairs are charged to expense as incurred .
when property is retired or .

Question: in the account for the allowance for doubtful accounts what was the percent of the change in the additions charged to expense from 2012 to 2013
Answer: -46%
Calculation: subtract(16.1, 29.7)