PACs are political committees not related directly to a political party, but rather affiliated with corporations, labor unions or other organizations. The committees contribute money to candidates and engage in other election-related activities so as to promote specific legislative agendas. Funds are gathered by voluntary contributions from members, employees or shareholders. PACs have increased significantly in influence and number in recent years: In 1976, there were 608 PACs; in 2010, there were about 5,400.