Problems $6-5$ Interpreting accounts receivable turnover $($LO$6-7)$

Packaging Corporation of America produces containerboard and white papers. WestRock Co$.$ manufactures paper products and corrugated products. Financial statement data for these two companies follow:

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Packaging Corporation of America$($$ in millions of dollars$)2015201620172018$Sales$$$$5,779\mathrm{.}0$$$6,444\mathrm{.}9$$$7,014\mathrm{.}6$Accounts receivable at December $31$$$636\mathrm{.}5689\mathrm{.}2830\mathrm{.}7901\mathrm{.}9$

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WestRock Co$.($$ in millions of dollars$)2015201620172018$Sales$$$$14,171\mathrm{.}8$$$14,859\mathrm{.}7$$$16,285\mathrm{.}1$Accounts receivable at December $31$$$1,575\mathrm{.}41,592\mathrm{.}21,886\mathrm{.}82,010\mathrm{.}7$

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Source:$$Computed from amounts in the Packaging Corporation of America and WestRock Co$.$ Form $10-$Ks for $20142018.$ In $2015$ and $2016,$ WestRock was known as WRKCo., Inc.

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Required:

Determine the receivables turnover ratios for both companies for $2016,2017,$ and $2018.($Use $365$ days in a year. Do not round intermediate calculations. Round your answers to $1$ decimal place.$)$

Which company collected its accounts receivable more quickly in $2018?$