Invictus, this is purely my opinion, but if the House of Representatives were there to represent the common people, the average net worth would be much lower.
For a different number, the median net worth in the House is ~$666,000 (http://www.marketplace.org/topics/economy/globalist-quiz/how-many-millionaires-are-congress) while the same statistic reads $120,000 for American families.
By that number, they are, by median, not average, since you're looking for a resistant figure, approximately five times richer than the rest of us.