comprehensive system of interrelated standards covering aspects from the design and construction to the maintenance and operation of buildings. LEED also grew from six committee volunteers to an organization of 119,924 staff, volunteers and professionals. LEED standards have been applied to approximately 83,452 registered and certified LEED projects worldwide, covering around 13.8 billion square feet (1.28 billion square meters). Many U.S. federal agencies, states, and local governments require or reward LEED certification. the leading four states, based on certified square feet per capita were Illinois, Washington, Massachusetts, and Colorado. However, lumber, chemical and plastics trade groups have lobbied to weaken the application of LEED guidelines in several southern states. In 2013, the states of Alabama, Georgia and Mississippi effectively banned the use of LEED in new public buildings, in favor of other industry standards that the USGBC considers too lax. Unlike model building codes, such as the International Building Code, only members of the USGBC and specific "in-house" committees may add to, subtract from, or edit the standard, subject to an internal review process. Proposals to modify the LEED standards are offered and publicly reviewed by USGBC's member organizations, which number almost 6660. USGBC's Green Business Certification Inc. (GBCI) offers various accreditations to people who demonstrate knowledge of the LEED rating system, including LEED Accredited Professional (LEED AP), LEED Green Associate, and LEED Fellow. GBCI also certifies projects pursuing LEED. Rating systems LEED has evolved since 1998 to more accurately represent and incorporate emerging green building technologies. The pilot version, LEED New Construction (NC) v1.0, led to LEED NCv2.0, LEED NCv2.2 in 2005, LEED 2009 ( LEED v3) in 2009, and LEED v4 in November 2013. LEED 2009 was depreciated for new projects registered from October 31, 2016. LEED v4.1 was released on April 2, 2019. LEED also forms the basis for other sustainability rating systems such as the U.S. Environmental Protection Agency's (EPA) Labs21 and LEED Canada. The Australian Green Star is based on both LEED and the UK's Building Research Establishment Environmental Assessment Methodology (BREEAM). LEED v3 (2009) LEED 2009 encompasses ten rating systems for the design, construction and operation of buildings, homes and neighborhoods. Five overarching categories correspond to the specialties available under the LEED professional program. That suite consists of: Green building design and construction (BD+C) – for new construction, core and shell, schools, retail spaces (new constructions and major renovations), and healthcare facilities Green interior