You receive a $9,000 check from your grandparents for graduation. You decide to save it toward a down payment on a house. You invest it earning 5% per year and you think you will need to have $18,000 saved for the down payment. How long will it be before the $9,000 has grown to $18,000?

To double the money you received from your grandparents, it will take _____ years.(Round to one decimal place.)