From 2015 through 2019, Avery owned a large assortment of inflatable slides and fun houses that she leases to others for various events. The value of the structures was $63,000 at the beginning of 2015 and the annual cash flows and end-of-year property are shown below.

AT Rental Value of

Year Income property, EOY

2015 $6,000 $65,000

2016 3,500 60,000

2017 6,800 56,000

2018 7,000 52,000

2019 8,300 45,000

Given this info, the rate of return for 2017 was _________%.