defunct, subsumed, or relocated) include: Demographics Depending on what geographic regions are included in the meaning of the term, the population of Silicon Valley is between 3.5 and 4 million. A 1999 study by AnnaLee Saxenian for the Public Policy Institute of California reported that a third of Silicon Valley scientists and engineers were immigrants and that nearly a quarter of Silicon Valley's high-technology firms since 1980 were run by Chinese (17 percent) or Indian descent CEOs (7 percent). There is a stratum of well-compensated technical employees and managers, including tens of thousands of "single-digit millionaires". This income and range of assets will support a middle-class lifestyle in Silicon Valley. Diversity Margaret O'Mara, a professor of history at the University of Washington, in 2019 pointed out problematic failures regarding diversity in Silicon Valley. Male oligopolies of high-tech power have recreated traditional environments that repress the talents and ambitions of women, people of color, and other minorities to the benefit of whites and Asian males. Gender In November 2006, the University of California, Davis released a report analyzing business leadership by women within the state. The report showed that although 103 of the 400 largest public companies headquartered in California were located in Santa Clara County (the most of all counties), only 8.8% of Silicon Valley companies had women CEOs. This was the lowest percentage in the state. (San Francisco County had 19.2% and Marin County had 18.5%.) Silicon Valley tech leadership positions are occupied almost exclusively by men. This is also represented in the number of new companies founded by women as well as the number of women-lead startups that receive venture capital funding. Wadhwa said he believes that a contributing factor is a lack of parental encouragement to study science and engineering. He also cited a lack of women role models and noted that most famous tech leaders—like Bill Gates, Steve Jobs, and Mark Zuckerberg—are men. As of October 2014, some high-profile Silicon Valley firms were working actively to prepare and recruit women. Bloomberg reported that Apple, Facebook, Google, and Microsoft attended the 20th annual Grace Hopper Celebration of Women in Computing conference to actively recruit and potentially hire female engineers and technology experts. The same month, the second annual Platform Summit was held to discuss increasing racial and gender diversity in tech. As of April 2015 experienced women were engaged in creation of venture capital firms which leveraged