Your retired client has accumulated investment and retirement assets totaling $3,560,000. Assume the client expects to live for another 28 years and that he assumes an annual inflation rate of 4.4 percent. To leave his heirs the future value of the $3,560,000 at the end of the 28 years, and maintain an inflation-adjusted lifestyle of $188,000 a year for all 28 years, the clients investments would have to earn an average of ______ percent a year for the entire 28 years.