There are 737 informal Member organizations listed in the Congressional Yellow Book or registered with the Committee on House Administration. According to self-reported information contained in the Congressional Yellow Book, the House's 650 informal Member organizations had from 1 to 315 members, with an average membership of 25, and the Senate's 87 informal Member organizations had from 1 to 61 members, with an average membership of 14. On average, House Members report membership in 38 informal Member organizations and Senators report membership in 18. Of these 737 informal organizations, as of June 17, 2014, 322 were registered with the Committee on House Administration as congressional Member organizations (CMOs).