The Heavens Gate Group have $42 million in cash. In order to reach the comet that will take them to a new world they need the $42 million to grow to $117 million. How many years will it take before the group can leave if they earn 5.8% per annum on their stash of cash? Assume annual compounding. (Enter your answer in years to 2 decimal places, e.g., 12.34)