The income statements for Lowe's Companies, Inc. (LOW), spanning the period 2014? 2016 (just before the housing crash, so these are representative years) are found here:

	2016		2015		2014
Net operating income (EBIT)	$4,971,000		$4,792,000		$4,149,000
Interest expense	(552,000)		(516,000)		(476,000)
Earnings before taxes	$4,419,000		$4,276,000		$3,673,000
Income taxes	(1,870,000)		(1,580,000)		(1,390,000)
Net income	$2,549,000		$2,696,000		$2,283,000

.

a. Calculate the time's interest earned ratio for each of the years for which you have data.

b. What is your assessment of how the firm's ability to service its debt obligations has changed over this period?