John wants to save for his retirement and decides to contribute to his employer's 401(k) plan. His employer matches 50% of his contribution up to a maximum of 6% of his salary. John's current salary is $60,000 per year, and he plans to retire in 30 years. John expects his salary to grow at a rate of 3% per year. He wants to have $1,000,000 in his retirement account when he retires. If the 401(k) plan earns an average annual return of 7%, how much should John contribute to the plan each year?