In a world characterized by rising interest rates, many financial institutions use a stepped yield GIC (Guaranteed Investment Certificate) to make investors believe that they are earning a higher yield than they actually are. In an example from a few years ago, the bank advertised the following yields:

Year 1: 2.0%

Year 2: 2.8%

Year 3: 3.5%

Year 4: 4.5%

Year 5: 8.5%

What is the annually compounded rate of return on this investment?