If you know a way of getting a constant 8% like clock work year after year for over 2 decades please let me know. There has been a lot of multiple year stretches where the S&P 500 produce 0 real gains. Just big swings up and big swings down.
Invest in electric transmission (American Transmission Company here in Wisconsin) companies which are guaranteed rate of return by the Public Service Commission and the rate of return is often in double digits. Unfortunately stock in these types of companies are not often open to the public....