A firm leases a car using a finance lease. The rental payments comprise 5 annual payments of $4,000 with the first rental payment paid one year after commencement of the lease. The fair value of the car at the commencement of the lease is $25,000 and the estimated fair value of the car at the end of the lease is $15,849. To the nearest whole per cent, what is the interest rate implicit in this lease.