Peter's retirement plan offers 2 choices for investment: invests in the total stock market or invests in Treasury Bills. He is not allowed to borrow or short. Moreover, his risk aversion nature makes him choose a combination of stock market fund and Treasury Bills that similar to a fund that has a beta of 1.27.

What is the percentage of investment in stock market should Peter do for his retirement plan if he wants to reach the desired level of market risk (with beta = 1.27) ?