Over the very long run, the stock market has had an inflation-adjusted annualized return rate of between six and seven percent. Another pattern: while stocks have certainly beaten inflation over the long run, they’ve done poorly within the high-inflation periods themselves: try the inflation-adjusted returns for 1916-1918, 1946-1947, and 1973-1981.
http://moneychimp.com/features/market_cagr.htm