The common-size income statement has much great information that you can extract to measure Costco's efficiency, but you are only focusing on net profit and membership fees, without focusing the reason behind the decline of net income (so does the declining ROE).

Moreover, financial ratio analyses are good, but you are not asking about who to invest, but to measure Costco's efficiency. Therefore, the focus should be the Costco's financial ratios over time.

identify Costco's CCC.

The SGR and ROE issues (some from discussion) remains untouched in the report. An in-depth analysis is required for both SGR and ROE to identify Costco's efficiency in 2001.