Top Contributing Interest Groups by Sector 2013-2014

source: opensecrets.org/industries/

* "[The Other] sector is home to a variety of industries that don't fall under any business, labor or ideological groupings. The biggest dollars, by far, come from the large and diverse group of donors listing their occupation as "retired." Other categories include educators, government employees (though not their unions), nonprofit organizations, religious groups and members of the armed forces."