About 65,000 people have become LEED Accredited Professionals (LEED APs) since the program began in 2000 as a way to recognize experts in the U.S. Green Building Council’s (USGBC’s) LEED Rating System. In November 2008 at the Greenbuild conference, the Green Building Certification Institute (GBCI), the organization that administers the LEED AP credential, announced substantial revisions to the program. After June 2009, existing LEED APs will have to opt in to an updated version of the program with continuing education requirements, while aspiring LEED APs will find that accreditation requirements have become more rigorous.