The S&P 500 Index Historical Returns of 8-10%
The S&P 500 Index originally began in 1926 as the “Composite Index” comprised of only 90 stocks. According to historical records, the average annual return since its inception in 1926 through 2018 is approximately 10%. The average annual return since adopting 500 stocks into the index in 1957 through 2018 is roughly 8% (7.96%). — Investopedia