Consider an annuity contract that pays out $48 at the end of each of the next four 6-month intervals (payments are to be made 6, 12, 18, and 24 months from today). What is this annuity's Macaulay duration (in years)? Assume this contract is currently trading at a yield of 5%.

Round your answer to 3 decimal places. For example if your answer is 5.5175, then please write down 5.518.

Hint: First price this contract, and then calculate its duration accordingly.