George is a financial planner in Ohio. He wants to join the National Association of Personal Financial Advisors (NAPFA), a professional organization for financial advisors. The membership dues for the NAPFA are $670 per year and must be paid at the beginning of each year. For instance, membership dues for the first year are paid today, and dues for the second year are payable one year from today. However, the NAPFA also has an option for members to buy a lifetime membership today for $7850 and never have to pay annual membership dues.

Obviously, the lifetime membership isnt a good deal if you only remain a member for a couple of years, but if you remain a member for 50 years, its a great deal. Suppose that the appropriate annual interest rate is 7.8%.

What is the minimum number of years that George must remain a member of the NAPFA so that the lifetime membership is cheaper (on a present value basis) than paying $67 in annual membership dues? (Note: Enter only a whole number by rounding your answer UP to the nearest year, i.e. 15.23 becomes 16).