During the same period, 2% fell asleep three times or more while driving.
The consequences of nodding off while at the wheel can be devastating. An estimated six people die each week in crashes caused by tired drivers.
The figures, from research by road safety charity Brake and breakdown recovery firm Green Flag, are from a survey of 4,640 drivers including 2,510 who drive for work.
The poll was conducted at random and included a range of motorists, including company car, LCV and HGV drivers.
“It’s crucial that companies introduce thorough procedures to ensure employees are not endangering themselves and others when driving for work,” said Cathy Keeler, head of campaigns for Brake.
“But drivers themselves must also take responsibility.”
“Getting behind the wheel when you’ve not had enough sleep is deadly.”
The research found that people who drive for work are more likely to drive after insufficient sleep.
Half of employees who drive for work say they sometimes drive after less than five hours’ sleep.
According to the Department for Transport, drivers who get behind the wheel after less than five hours’ sleep have only a one in 10 chance of staying fully awake on a lengthy journey.
David Richards, marketing director for driver training company DriveTech, said: “Driving tired is a very serious issue and journey planning is the key to being safe.”