All investment returns globally are annual....who the hell offers 10 to 12 percent over 20 years.
Your intellect is apparent so best you stay queit. And do the maths its not 40 percent over 20 years. Learn basics. This is elementary maths
First, do some research to understand how many projects are built with 30 % and above ROI in mind and then we will take this further. Come on now, do your research.