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There is no tax, just a distribution of coins. If 10% of new coins being emitted per year, then rougly the same amount of money will be spent mining them. The same goes for 5%, 2% of the market cap and so on. Money in, money out - no tax!
Call it "service fee" or "inflation," call it whatever you want, but ~10% of Bitcoin's market cap will be spent every year to maintain current level of security. For now inflation is footing the bill, but once block reward halves, either security will suffer, or tx fees go way up.