3M Co. (ticker symbol MMM) is a large American corporation. It is considered a dividend aristocrat because the company has been able to increase its dividend payouts for 25 consecutive years or more. 3M Co.s stock currently trades at $155.00. Its most recent full-year dividend was $5.75, and management has established a plan to grow the dividend by 2.1% each year.

What is the required rate of return for 3M Co., according to the Gordon growth model? Assume last year's full dividend has just been paid out. Give your answer as a percentage number, rounded to 2 digits. (For example, if you find k=12.232% or k=0.12232, then type in 12.23 as your answer.)