Over long-term historical 20-year rolling periods, the United States stock market—typically benchmarked by the S&P 500 index—has delivered an average annualized total nominal return ranging roughly between 9 and 10 percent before adjusting for inflation. When factoring in historical inflation rates, the average annualized real return generally settles closer to 6 or 7 percent, though actual performance fluctuates significantly depending on specific entry and exit baseline years within economic cycles.