Learning World, Inc. has two divisions: Test Preparation and Language Arts. Results (in millions) for the past three years are partially displayed here:

	Operating Income	Operating Revenues	Total Assets	Operating Income/Operating Revenue	Operating Revenues/Total Assets	Operating Income/Total Assets
Test Preparation Division
2015	700	8750	2500	?	?	?
2016	850	?	?	10%	?	40%
2017	1120	?	?	11.2%	4.0	?
Language Arts Division
2015	620	2480	1150	?	?	?
2016	?	3525	2350	20%	?	?
2017	?	?	2500	?	2.0	25%
Learning World Inc
2015	1320	11230	4050	?	?	?
2016	?	?	?	?	?	?
2017	?	?	?	?	?	?

Complete the table by filling in the blanks. (Round all dollar amounts to the nearest dollar, percentages to the nearest tenth percent, X.X%, and ratios to one decimal place.)

Use the DuPont method of profitability analysis to explain changes in the operating-income-to-total-assets ratios over the 2015dash2017 period for each division and for Learning World as a whole. Comment on the results.