Your retired client has accumulated investment and retirement assets totaling $5,680,000. Assume the client expects to live for another 17 years and that he assumes an annual inflation rate of 2.1 percent. To leave his heirs the future value of the $5,680,000 at the end of the 17 years, and maintain an inflation-adjusted lifestyle of $213,000 a year for all 17 years, the client's investments would have to earn an average of ______ percent a year for the entire 17 years.