Apple CEO Tim Cook has lost some footing in a ranking of chief executives.
Jobs site Glassdoor has released its annual list of the highest-rated CEOs in the world as judged by their employees. The measure, which comes from evaluations company employees share on the Glassdoor page, uses a percentage scale to determine how many employees “approve” of their top boss. Last year, Apple (AAPL) CEO Tim Cook reached eighth place in the ranking with a 96% approval rating. In 2017, he has fallen to 53rd place with a 93% approval rating.
Glassdoor doesn’t provide insight into why executive approval ratings fluctuate, so it’s unknown why Cook is down year-over-year.
At the top of the list if Clorox (CLX) CEO Benno Dorer, who achieved a 99% rating in the evaluation. World Wide Technology’s Jim Kavanaugh and Boston Scientific’s (BSX) Michael Mahoney also mustered 99% approval ratings. Tesla (TSLA) CEO Elon Musk took Cook’s eighth place with a 98% approval rating.
Get Data Sheet, Fortune’s technology newsletter
Not many executives or companies put much stock in CEO rankings, including the one issued by Glassdoor. While it provides some insight into employee views on chief executives, it largely comes from a small subset of a company’s employees. Any chief executive’s ranking, in other words, might not tell the whole story about the person and how he or she is really viewed by the workforce.
Still, the findings suggest that in general, chief executives aren’t so well-liked among employees. In fact, the average CEO approval rating is 67%—a far cry from Dorer’s 99% and Cook’s 93% approval rating.
One other tidbit from the Glassdoor study: Uber co-founder Travis Kalanick, who stepped down from his post as CEO under intense pressure on Wednesday, had an above-average 77% approval rating.