Is your job keeping you up at night? If you work for Amazon, Apple, GM or 22other Fortune 100 companies surveyed by Israeli startup Dayzz and  market-research firm Ipsos, says the answer is probably a big yawning yes.

Dayzz, whose app creates a customized sleep-training plan for poor sleepers, says sleep experts agree that most people need seven to nine hours of sleep a night. The average number of hours per night among the employees surveyed is just 6.4.

In some big companies, many employees average 5.5 hours of sleep (or less) per night, including 61% of employees surveyed at Chevron, 45% at GM, 40% at ExxonMobil and 34% at Apple, Amazon and GE.

Dayzz points to a study from the medical journal Sleep that found a person sleeping less than six hours a night has cognitive impairment comparable to someone who has been awake for 24 to 48 hours straight.

People who answered the Dayzz survey said that their drowsiness puts themselves and other drivers at risk an average of three days a week.At GM, 77% of employees feel they incur risk five to seven days per week; 38% at GE and 34% at Apple estimated similarly.

Based on the survey results, Dayzz calculated an overall corporate “sleep score,” giving each company a grade between 4 and 100 based on their employees’ average sleep time, average sleep loss, and amount of quality sleep vs. poor quality sleep due to work-related matters.

The companies that ranked the best: Wells Fargo, Cisco, IBM, Facebook and Dell.

The companies that ranked the worst: ExxonMobil, Amazon, GE, Intel and GM.

Said Amir Inditzky, CEO of Dayzz: “Employees’ insufficient sleep costs approximately $411 billion per year, and roughly 1.2 million working days are lost annually due to poor productivity.”

Dayzz, established in 2017 by Israeli nutrition and health product developer and distributor Maaborot Products, also found that more than 50% of employees surveyed believe that a sleep wellness program could increase their job satisfaction.