the first pension check was received on june 15 2006 during his years of employment 633747

Richard Brown, who retired on May 31, 2006, receives a monthly pension benefit of $700 payable for life. His life expectancy at the date of retirement is ten years. The first pension check was received on June 15, 2006. During his years of employment, Brown contributed $12,000 to the cost of his company’s pension plan. How much of the pension amounts received may Brown exclude from taxable income for the years 2006, 2007, and 2008?