The following information (in millions) was taken from the December 31 financial statements of Canadian National Railway Company:

		2017				2016				2015
Accounts receivable, gross			$1,000				$903				$885
Allowance for doubtful accounts			16				28				7
Accounts receivable, net			984				875				831
Revenues			13,041				12,037				12,611
Total current assets			2,190				2,107				2,153
Total current liabilities			3,983				3,008				2,998

Calculate the 2017 and 2016 current ratios

Calculate the receivables turnover and average collection period for 2017 and 2016.