Keeping a job, any job, for 20 years or more is becoming rarer and rarer. The feat may be uniquely treacherous for the chief executive officer of a publicly traded company that is judged on quarterly performance. As goes the company, so goes the CEO’s career.

Among the companies that comprise the S&P 500 index, just 30 recent CEOs have held their jobs for 20 or more years. For Americans born between 1957 and 1964, men held an average of 11.8 jobs in their working careers and women held 11.5 different jobs. Job changes could be due to promotions, transfers or leaving, voluntarily or otherwise. According to U.S. Bureau of Labor Statistics data for 2016, the average job tenure for an employee is just 4.2 years.

…Researchers at MyLogIQ, a public company intelligence provider, have combed through the data and provided the following list of 30 CEOs who have held their jobs at an S&P 500 company for 20 years or more in its “CEO Tenure at S&P 500 companies.” All 30 are men, and they range in age from 54 to 83. We’ve noted which of these CEOs are also founders, co-founders or scions of either.