Taxes are computed on income not revenue.So? Revenue is generated by sales (prices). If income taxes are only 2% of revenue, if you remove the income taxes - how much could prices go down for WalMart? No more than 2%.
Since taxes are computed on income, not revenue, and income is what determines if a company is successful or not, you must compare income tax as a percentage of income. WalMart pays 35% of its income to income tax.
Revenue - Expense = Income.
That's not the case but in any event trying to present numbers as a % of revenue is misleading when talking about taxes since additional tax costs have already been embedded into prices by the action of any income-based tax system.
Those "hidden taxes" are part of that revenue you mention and probably quite a good bit of it. And indeed taxes are computed on income and not revenue.