How would you describe the relationships between years for the Dep Ex as a % of Gross PPE? Not looking for calculations, looking for an interpretation of how the company is doing based on these figures and what might be causing it to be so stable or unstable. Don't worry about the calculations. Just an interpretation please.

Depreciation Expense as % of Gross PPE
	2013	2012	2011
Depreciation Ex	345	320	306
Gross PPE	$ 4,980	$4,380	-
	6.93%	7.31%	-%