republic services , inc .
notes to consolidated financial statements 2014 ( continued ) high quality financial institutions .
such balances may be in excess of fdic insured limits .
to manage the related 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 small-container , large-container , municipal and residential , and energy services 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 accounts receivable represent receivables from customers for collection , transfer , recycling , disposal , energy services and other services .
our receivables are recorded when billed or when the related revenue is earned 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 and customer credits , 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: .

2018
2017
2016
Balance at beginning of year
$38.9
$44.0
$46.7
Additions charged to expense
34.8
30.6
20.4
Accounts written-off
( 39.4)
( 35.7)
( 23.1)
Balance at end of year
$34.3
$38.9
$44.0

restricted cash and marketable securities as of december 31 , 2018 , we had $ 108.1 million of restricted cash and marketable securities of which $ 78.6 million supports our insurance programs for workers 2019 compensation , commercial general liability , and commercial auto liability .
additionally , 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 processing 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. .

Question: Analyse this data from a financial earnings document. as of december 312018 what was the percent of restricted cash and marketable securities dedicated to the support our insurance programs
Choices:
0.7271
1
8496.66
0.8326
22.2494
Correct choice index: 0