NewCorp offers its employees a 401(k) plan. The company matches employee contributions at 50% up to 10%. Randy just started working for NewCorp. His annual salary is $61,575, and he's paid monthly. Randy would like to have $250,000 in his 401(k) when he retires in 32 years. If his investments earn 7.5%, what percent of his salary should he contribute to his account