Wall Street is pulling further from its record after reports on Friday showed worries about President Donald Trump's policies may be hitting the U.S. economy. The S&P 500 was down 0.4% in morning trading,

U.S. stocks tumbled on Friday, extending their selloff in the wake of dour economic reports and closing the book on a holiday-shortened week fraught with new tariff threats and worries of softening consumer demand.

However, the S&P 500 ( ^GSPC 0.24%) is generally considered the best barometer for the overall U.S. stock market due to its scope and diversity. Read on to see the S&P 500's average return over the last decade, and to learn what Wall Street expects in the future.