FYI: The stock premium—the annual average return of stocks minus the annual average return of one-month Treasury bills—has been high, attracting investors to the stock market. For the period 1927–2017, it averaged 8.5%. There have also been size (return of small stocks minus return of large stocks) and value (return of value stocks minus return of growth stocks) premiums of 3.24% and 4.82%, respectively.
Regards,
Ted
https://www.etf.com/sections/index-investor-corner/swedroe-be-prepared-losses?nopaging=1