William "Bill" D. Green (born August 1953) is an American business executive.
 He is the retired (as of 2/1/2013) executive chairman of the global Accenture management consulting firm.
Arthur D. Little is an international management consulting firm originally headquartered in Boston, Massachusetts, United States, and formally incorporated by that name in 1909 by Arthur Dehon Little, an MIT chemist who had discovered acetate.
 Arthur D. Little pioneered the concept of contracted professional services.
 The company played key roles in the development of business strategy, operations research, the word processor, the first synthetic penicillin, LexisNexis, SABRE and NASDAQ.
 Today the company is a multi-national management consulting firm operating as a partnership.
Diamond Management & Technology Consultants (casually referred to as Diamond) was an independent management consulting firm founded in 1994, headquartered in Chicago, IL with satellite offices in Hartford, CT, New York City, Washington DC, London, and Mumbai.
 It was acquired by the British firm, PwC in 2010.
 Diamond was a smaller player among companies such as Mercer Management Consulting, Deloitte Consulting, and Accenture.
 The industry segments under which Diamond operated include consumer packaged goods, financial services, and health-care, among numerous others.
Oliver Wyman is an international management consulting firm with a large focus on banking and financial services.
 Founded in 1984, the firm adopted its current form in May 2007, when Mercer Oliver Wyman joined with Mercer Management Consulting and Mercer Delta to become one firm named Oliver Wyman.
 As of fiscal year 2016, it was the fourth biggest management consulting firm in the world in terms of revenue, ranking just below the Big Three.
 It is part of the Oliver Wyman Group, a business unit of Marsh & McLennan.
Accenture PLC is a global management consulting and professional services company that provides strategy, consulting, digital, technology and operations services.
 A Fortune Global 500 company, it has been incorporated in Dublin, Ireland, since 1 September 2009.
 In 2017, the company reported net revenues of $34.9 billion, with more than 425,000 employees serving clients in more than 200 cities in 120 countries.
 In 2015, the company had about 130,000 employees in India, about 48,000 in the US, and about 50,000 in the Philippines.
 On August 29, 2017, Apple Inc.
 announced a partnership with Accenture to create iOS business solutions.
 Accenture's current clients include 94 of the Fortune Global 100 and more than three-quarters of the Fortune Global 500.
NouvEON (officially NouvEON Technology Partners) is an employee-owned Management Consulting and Information Technology Consulting firm.
 NouvEON offers strategic- and project-based management consulting services to improve business performance for their clients.
 Headquartered in Charlotte, North Carolina, NouvEON also has offices in Raleigh, North Carolina and professional consultants in Philadelphia, Pennsylvania; Baltimore, Maryland; Minneapolis, Minnesota; and Houston, TX.
Public sector consulting in the US usually refers to the branch of management consulting that works with local and federal governments as well as government agencies.
 Several major management consulting firms (e.g.: McKinsey, BCG, Booz&Co, Monitor) do public sector engagements as part of their overall business.
 The biggest public sector consulting firm in the UK is PA Consulting Group.
Amritt Ventures is a global management consulting firm based in the Los Angeles area.
 The stated purpose of the company is to aid North American and European firms in becoming familiar with routine Asian business practices, specifically in marketing their products to India and China, both of which are BRIC countries.
 Amritt has recently been ranked as one of the Top 10 Consulting Companies of India.
 Their executives have contributed to various financial magazines, including BusinessWeek and advised both US companies and the US president on doing business with India.
 Notable clients of Amritt include Kraft Foods, Johnson & Johnson, the British company Reckitt Benckiser, and the French media conglomerate Vivendi.
The Boston Consulting Group (BCG) is an American worldwide management consulting firm with 85 offices in 48 countries.
 The firm advises clients in the private, public, and not-for-profit sectors around the world, including more than two-thirds of the Fortune 500 and is one of the 'Big Three' strategy consulting firms (MBB).
 Considered one of the most prestigious management consulting firms in a branche-internal survey, BCG was ranked third in "Fortune"'s "100 Best Companies to Work For" in 2017.
Katzenbach Partners was a small American management consulting firm.
 In 2009 it became a part of the global management consulting firm Booz & Company.

Question: How many of the Fortune Global 100 companies are clients of the management consulting firm that William D. Green retired from in 2013?
Answer: 94