Niendorf Incorporated needs to raise $25 million to construct production facilities for a new type of USB memory device. The firm's straight nonconvertible debentures currently yield 9.5%. Its stock sells for $25 per share, has an expected constant growth rate of 6.5%, and has an expected dividend yield of 7%, for a total expected return on equity of 13.5%. Investment bankers have tentatively proposed that the firm raise the $25 million by issuing convertible debentures. These convertibles would have a $1,000 par value, carry a coupon rate of 8.5%, have a 20-year maturity, and be convertible into 33 shares of stock. Coupon payments would be made annually. The bonds would be noncallable for 5 years, after which they would be callable at a price of $1,075; this call price would decline by $5 per year in Year 6 and each year thereafter. For simplicity, assume that the bonds may be called or converted only at the end of a year, immediately after the coupon and dividend payments. Also assume that management would call eligible bonds if the conversion value exceeded 20% of par value (not 20% of call price). At what year do you expect the bonds will be forced into conversion with a call