Volunteerism

I was watching the C-Span interview last night (which was from earlier this year) at the national Mitt blogsite. The interviewer mentioned that mitt did not take a salary during his time at the Olympics, and has not during his time as governor. To be more specific, he has recieved salries from both positions, but has elected to give 100% of that money away. Mitt was asked to comment on this. He replied that since he has made more than enough money for his and his families needs in his business career, he viewed these two positions as volunteer service.

Is this common among politcians? If not I am completely blown away by how selfless this is!