You should consider the following model
Where A is the annuity (the expected return), P the principal (initial amount invested), r is the rate and n is the term (or number of years invested).
The only question I have is, have you invested for 5 years or 6? If your beginning was the start of year one and the end was the start of year 6 then this would be years. If your end point was the end of year 6 then you would have .
Here is my attempt with
This will give you the required rate. After you have this you can solve for the next year by substituting the value into r below. (Once again dependant on that start year/end year condition)