Ah, sleep...Just thinking about it makes you, well, sleepy. But how does your sleep rate? Are you getting enough? If you live in the U.S., maybe not. So who is sawing the most logs? We’ve got some stats that might have you tossing and turning.

Here are the countries that sleep the most and least.

In 2016, researchers at the University of Michigan analyzed the sleep patterns of thousands of people around the world who used the mobile phone app ENTRAIN. The app was designed to help travelers minimize the effects of jet lag. But the sleep data that people punched in gave the researchers a treasure trove of real world sleep statistics.

Most people in the data set schedule between seven and eight hours of sleep a night, with a mean of 7.88 hours.

That all depends, says Danny Forger, senior author of the ENTRAIN study. "People set guidelines all the time -- you need eight hours, you need seven hours -- but we've found that 'normal' sleep varies tremendously depending on your age, sex and what country you are in," he said.

According to the ENTRAIN data, people in the Netherlands were the most well-rested, averaging 8 hours and 12 minutes of sleep a night.

Residents of Singapore and Japan had the shortest sleep duration of the 20 countries represented in the study, getting an average of 7 hours and 24 minutes of shut-eye a night.

In the United States, the average sleep duration was 7.87 hours. That put Americans between Italy and China in the survey.

In addition to the Netherlands, other countries racking up more than 8 hours per night were New Zealand, France, Australia and Belgium.

Other countries reporting significantly less than 8 hours per night were Brazil, Germany and Hong Kong.

According to the study, gender plays the biggest role in how long a person sleeps. On average, women schedule 8.07 hours of sleep, while men schedule 7.77 hours. Women both go to bed a bit earlier than men and wake up a bit later. The authors say this effect is most pronounced among people 30 to 60.

Age also seems to be an important factor for when people sleep. On average, older people in the ENTRAIN data schedule sleep earlier than younger people.

Despite black-out curtains, artificial lights and alarm clocks, solar cues -- the time of sunrise and sunset -- still have a significant effect on sleep patterns.

Both sunset and sunrise had a bigger effect on when people woke up, compared to when they went to sleep. Later sunrises (after 6:30 a.m.) were associated with later wake times and bedtimes. Later sunsets were also associated with later wake times and bedtimes, but the effect of sunset on what time a person went to bed at night was weaker than what models predicted.

A 2009 study conducted by the Organization for Economic Cooperation and Development had France as the developed nation where people get the most sleep. The French reported an average of 530 minutes of sleep per night. That’s almost 9 hours.

Koreans came in last in that survey, logging just 469 minutes of sleep per night.

The non-profit National Sleep Foundation released an International Bedroom Poll in 2013. It charted the sleep habits of six countries: the U.S., Canada, Mexico, the United Kingdom, Germany and Japan. In this survey, Japanese people reported sleeping the least, averaging 6 hours and 22 minutes per work night.

Right behind the Japanese were American sleepers. They averaged a bit more than the Japanese surveyed, but only 6 hours and 31 minutes per work night. And to make matters worse, 21 percent of American reported sleeping fewer than 6 hours per night during the work week. C’mon, America! Get to bed!

The good news for Americans and Japanese: Among this group, they were more likely to take a nap. About half of both Japanese and Americans reported taking at least one nap in the previous two weeks. That hits the spot!

In that Sleep Foundation survey, 66 percent of Japanese reported getting less than 7 hours of sleep on work nights. So did 53 percent of Americans, 39 percent in the United Kingdom, 36 percent of Germans, 30 percent of Canadians, and 29 percent of Mexicans.

Americans had the dubious honor of leading that survey in the percentage of people getting fewer than six hours of sleep per work night, at 21 percent. Right behind were Japan (19 percent) and the United Kingdom (18 percent). Mexico, Germany and Canada did better at 11 percent, 10 percent and 7 percent, respectively.

Only 44 percent of Americans reported getting a good night’s sleep every weeknight or almost every weeknight. And 25 percent of Americans said they never get a good night’s sleep.

According to a 2016 study by the U.S. Centers for Disease Control, more than a third of American adults are not getting enough sleep on a regular basis. Experts recommend that adults age 18–60 sleep at least 7 hours each night.

Sleep is vital to a person’s physical and emotional health. According to the U.S. Department of Health and Human Services, studies have shown that sleep deficiency alters activity in some parts of the brain. People who are sleep deficient may have trouble making decisions, solving problems, controlling emotions and behavior, and coping with change. Sleep deficiency also has been linked to depression, suicide, and risk-taking behavior.

Ongoing sleep deficiency is linked to an increased risk of heart disease, kidney disease, high blood pressure, diabetes, stroke, and obesity.

The National Sleep Foundation has some advice for those looking to get a better night’s sleep. Some tips: Exercise during the day, stick to a sleep schedule that has you going to bed and waking up at the same time each day, and get the TV of your bedroom.

The CDC has some helpful advice, too: Make sure your room is quiet dark and relaxing, and avoid big meals and alcohol before bedtime.