There are 10 bonds, each one with par value of $100, 4% semiannual coupons and redemption value of $120. The bonds are purchased for $106 each. One bond will mature in 11 years, the second in 12 years, and so on, with 10th bond maturing in 20 years. How many of the bonds will earn a nominal yield rate of at least 4.5% per annum compounded semiannually?