Your parents will retire in 20 years. They currently have $308,151, and they think they will need $1,735,819 at retirement. Assuming they don't save any additional funds, the annual interest rate they must earn to achieve their goal would be %. Margin of error for correct responses: +/.03(%). Rounding and Formatting instructions: Do not enter dollar signs, percent signs, commas, X, or any words in your response. not round any intermediate work, but round your * final* response to 2 decimal places (example: if your answer is 12.3456,12.3456%, or $12.3456, you should enter 12.35)