May I ask what is the factors of declining in the return on total assets percentage?Rather than decreasing in net surplus, does the total assets influenced the percentage? For instance, if the total inventory keep increasing every year, does it affect the return on total assets percentage?

Return on Assets is a function of profitability and turnover as much as it is a reflection on financial management. It is to be expected that increases in inventory support increased turnover, If these are properly in balance then they won't affect the ratio greatly. Inventory is usually only a small part of the assets employed in a business.

So obviously the assets held affects the ratio and a low ratio may indicate underemployed assets. The trend is important. I prefer EVA as a measure of overall financial management