The Congressional seating chart is based on which industry has given the most to each member of Congress over his or her career. This means that members are seated according to the industry that has given a plurality of donations. For example, a member who received 20% of her donations from financial firms and 19% from unions would be seated in the finance, insurance, and real estate bloc.
Corporate donations include money given by companies' employees and political action committees, unless noted otherwise. Counting employees as corporate donors isn't perfect: You may not give to a candidate with your employer's interests in mind. Yet excluding individual contributions would overlook "bundled" gifts from a company's employees as well as gifts from executives and their families.
All data was current at the time it was compiled.