Today is 1 July, 2019. Siobhn has a portfolio which consists of two different types of financial instruments (henceforth referred to as instrument A and instrument B). Siobhn purchased all instruments on 1 July 2013 to create this portfolio, which is composed of 40 units of instrument A and 29 units of instrument B. Instrument A is a zero-coupon bond with a face value of $100. This bond matures at par. Its maturity date is 1 January 2029. Instrument B is a Treasury bond with a coupon rate of j2=3.84% p.a. and a face value of $100. This bond matures at par. Its maturity date is 1 January 2022. Calculate the current duration of Siobhns portfolio using a yield to maturity of j2=4.14% p.a. Express your answer in terms of years and round your answer to two decimal places.