Ivanhoe Solutions, Inc., has just invested $4,523,700 in new equipment. The firm uses a payback period criteria of rejecting any project that takes more than four years to recover its costs. Management anticipates cash flows of $693,400, $797,300, $888,500, $1,347,800, $2,045,400, and $2,452,700 over the next six years. (Round answer to 2 decimal places, e.g. 15.25.) What is the payback period of this investment?