An Amazon fulfillment center in New York City promoted 220 people among its more than 5,000 employees last year, The New York Times reports. The rate — which is less than half of Walmart’s in-house promotion rate, the Times notes — appears to be part of a larger trend at the company.

David Niekerk, Amazon’s former vice president of human resources who retired in 2016, told the Times the company intentionally limited upward mobility for hourly workers, adding that his request to create more leadership roles for those employees was shot down in favor of hiring managers straight out of college. In contrast, more than 75 percent of Walmart’s store manageArs began as hourly employees.

The philosphy stems, in part at least, from Amazon founder Jeff Bezos, Niekerk suggested. Per the Times, Niekerk said Bezos didn’t want hourly workers sticking around too long because a “large, disgruntled” work force could be a threat to productivity. So, applicant pools are reportedly steep by design, and the company offers incentives to leave, including payment for resignation and free courses to train associates in other fields, an employee at the New York fulfillment center said. Read more at The New York Times.