Fortune’s 2020 list of the 100 Best Companies to Work For  is out, and accounting firms are again among them. All four of the Big Four firms are in the top 50, as is Plante Moran.

This is the largest annual ongoing workforce study in America, covering over four million employees. Companies must have over 1,000 employees and apply to Great Place to Work, which conducts the confidential employee surveys and evaluates the applicants’ policies and programs.

The ranking results primarily from an evaluation of employee survey questions. It is driven 85 percent by employee reports of their experiences with reaching their full potential and trust and 15 percent by their assessment of effective leadership, ability to contribute new ideas, and company values.

Here’s how the accounting firms fared:

No. 21 Plante Moran has made the list 22 years in a row. Its website states flexibility and camaraderie are two things that got it there, along with its philosophy of “being a people firm disguised as an accounting firm.” It is much smaller than its fellow award-winners in the Big Four, with approximately 3,000 employees in four states. Managing Partner Jim Proppe says the firm’s success begins and ends with its team, and that culture is something it works on continuously.

Plante Moran’s workforce is 47.8 percent women and 11 percent minorities, and it has inclusion, diversity, and “Women in Leadership” programs to recruit, develop, retain, and advance employees.

No. 25 Ernst & Young LLP moved up the list from No. 34 last year and has also been named 22 years in a row. Employees responded they were happy working at EY because of the opportunities to learn and develop and a culture that promotes excellence and creativity.

EY’s website states its purpose is to build a better working world, by developing outstanding leaders that can create positive change. EY has over 48,000 employees in the United States, and its workforce is 44.8 percent women and 37.5 percent minorities. It received positive employee feedback for filling 28 percent of its job openings last year internally and for 42 percent of new hires coming from employee referrals.

No. 32 KPMG LLP attributes investments in its culture to the reason it has been recognized on this list for the 13th time. Its workforce of about 32,000 U.S.-based employees is 44.7 percent women and 33.4 percent minorities, and employees cited diversity and how every voice on the team is heard and considered as reasons KPMG ranked so high.

No. 36 PricewaterhouseCoopers also climbed in the ranking from No. 44 last year and has been on the list for 16 years in a row. Its U.S. workforce of approximately 44,000 is 45.6 percent women and 32.7 percent minorities, and its U.S. Chairman Tim Ryan remains committed to the CEO Action for Diversity and Inclusion initiative that he launched in 2017.

No. 45 Deloitte declined in the ranking from No. 26 last year, but it has been on the list for 21 years. It has changed CEOs in the past year and did have some voluntary employee turnover.

Employees gave Deloitte favorable ratings in the survey for work culture and opportunities to learn and improve. The company’s website describes its goal to be an organization where people can thrive. Its U.S. workforce is almost 66,000 and is 42.7 percent women and 44.1 percent minorities.