Below are some summary numbers for a firm for fiscal years 2004 and 2005 (in millions of dollars).

	2004		2005
Sales	12,257		12,867
Operating income (after tax)	858		772
Net financial expense (after tax)	56		98
Comprehensive income	802		674
Average net operating assets	4,903		4,949
Average common equity	3,503		2,149

Calculate return on common equity (ROCE), return on net operating assets (RNOA), and net borrowing cost (NBC) for the two years.

How much of the change in ROCE over the two years is due to:

Change in profit margin

Change in asset turnover

Change in financial leverage

Change in borrowing costs?