You are strongly of the opinion that interest rates are going to fall within the next six months. Consequently, you are considering investing in an eight-year treasury bond that is currently trading at a yield to maturity of 2.20%. The bond has a coupon rate of 2.20% and pays coupon interest semi-annually. Your belief is that the yield to maturity on these bonds will fall by 40 basis points to 1.80% within the next six months. 

What percentage return will you earn if you buy the bonds now and sell them in six months, if your belief is realised?