What is the average stock market return over 30 years?

Looking at the S&P 500 for the years 1991 to 2020, the average stock market return for the last 30 years is 10.72% (8.29% when adjusted for inflation). Some of this success can be attributed to the dot-com boom in the late 1990s (before the bust), which resulted in high return rates for five consecutive years.