Problem as usual are taxes and inflation. You must get 3,5% after compensating both. While most European countries report an inflation of 5%, real monetary inflation (M2) is often 10-20%.

You can look at it also as 3,5% above S&P500 and after taxes. Then you're safe.

But remember Genesis 3:17: "cursed is the earth in thy work; with labour and toil shalt thou eat thereof all the days of thy life. "