Spurred by a ludicrous cost of living and one of the fiercest housing markets in the world, Silicon Valley has the highest growth rate of outbound job searches of any tech hub in the U.S. -- putting the region at risk of a brain drain, according to a study released Tuesday.

Among job seekers in San Francisco and San Jose, 44 percent are looking for roles outside of their region, according to an analysis conducted by Indeed, a job searching website. Silicon Valley's outbound job searches have grown by 67 percent in the past five years. This growth rate is higher than that of other American cities with large tech sectors, including New York, Seattle, Boston and Austin.

"Silicon Valley job seekers, including highly paid tech workers, are looking for jobs outside their own metro area at a much higher rate than other metros," said Raj Mukherjee, Indeed's senior vice president of product, in a statement. "This implies they are aware that highly paid job opportunities are being created not just in Silicon Valley but in other parts of the U.S."

Indeed's analysis found that among those between 18 and 24 in Silicon Valley, 49 percent are looking for jobs elsewhere. Surprisingly, this number climbs higher among older professionals, who typically lead more settled lives and are not looking to relocate. Indeed found that among those between 45 and 54 years old, 59 percent are conducting outbound job searches.

"It begs the question, why are these people looking to migrate for their next job?" Mukherjee said. "We think it is because living in the Valley has become unaffordable for so many people or it could be desire for a better work-life balance."

Contrasting Silicon Valley is Austin, where only 34 percent of job seekers are looking for jobs elsewhere -- a decrease of 33 percent in the last five years. Austin is also experiencing 13 percent growth in inbound job searches, the highest among any tech hub.

According to a study earlier this year, the average annual salaries for software engineers in Silicon Valley and Austin stood at $134,000 and $110,000, respectively. However, when adjusted for cost of living, Austin developers live the equivalent lives of Bay Area engineers who earn $198,000 annually.

"We found that Silicon Valley job seekers are increasingly interested in leaving -- especially older ones -- while Austin job seekers are increasingly looking locally for their next opportunity," the Indeed report said.