For the third consecutive year, Silicon Valley saw more people leave than come in.

That's according to the 2020 Silicon Valley Index, the annual look at the region's economy by Joint Venture Silicon Valley, which said housing remains unaffordable and income and wealth inequality are "more pronounced than ever." Included in the group's definition of Silicon Valley are Santa Clara and San Mateo counties, plus parts of Alameda County (Fremont, Newark and Union City) and Scotts Valley in Santa Cruz County.

"The granularity of migration data in this year's Index is eye-opening – we're essentially turning over our population by nearly 5% every year, with the influx of foreign immigrants increasing our region's diversity and tech talent base," said Rachel Massaro, Joint Venture vice president and director of research.

• From July 2018 to July 2019, the region saw its lowest population growth rate since 2005, adding less than 7,000 residents.
• Where Silicon Valley residents are moving: 29% move elsewhere in the Bay Area, while the rest move to other parts of California, Washington, Texas, Arizona, Nevada and New York.
• From July 2016 to July 2019, Silicon Valley gained 58,738 foreign immigrants but lost 69,208 residents to other parts of California and the United States.
• The share of foreign-born residents reached 38% in 2018 (up from 28% in 1960 and 16% in 1940). The share was particularly high "for employed residents and those working in technical occupations," according to the index.