You are considering purchasing a warehouse. The cost to purchase the warehouse is $500,000. Renting the equivalent space costs $20,000 per year. If the annual interest rate is 6%, at what rate must rental cost increase each year to make the cost of renting comparable to purchasing? Assume that the rent will be paid at the end of each year. Rental costs must grow at a rate of _________ % per year for the cost of renting to be comparable to the cost of purchasing the warehouse. (Round to one decimal place.)