The duration of the floating side is 1/2 the time until the next reset date. Since this is an annual pay swap the duration of the floating side is 1 x .5 = .5 or 1 divided by 2 = .5. The duration of the fixed side of a swap is approximately .75 to the time until maturity. If we take a different example of a 4 year swap with semi-annual payments the duration of the fixed side would be .75 x 4 = 3 and the duration of the floating side is .5 / 2 = .25. | 
