A cannery is considering installing an automatic case-sealing machine to replace current hand methods. If they purchase the machine for $5000 in June, at the beginning of the canning season, they will save $500 per month for the 4 months each year that the plant is in operation. Maintenance costs the case-sealing machine are expected to be negligible. The case-sealing machine is expected to be useful for five annual canning seasons and then will have no salvage value. What is the nominal annual rate of return as a percentage?