Not sleeping enough can have serious health costs. But it can have pretty big financial costs, too, according to a new study in the journal Sleep. Insomnia is "an under-appreciated problem," says lead author Ronald Kessler, at Harvard Medical School. "Americans are not missing work because of insomnia," but they are doing lousy work because they're tired. "It's difficult to find a condition that has a greater effect on productivity." How great is the hit to our economy, and our lives? Here, the numbers:

Days the average worker loses to insomnia each year

Estimated cost of that insomnia, in lost productivity, per worker

50-70 million
Estimated number of American employees who report being impaired during the day due to poor sleep

$63.2 billion
Cost of that lost productivity for the nation as a whole

Percentage of U.S. workers sleep-deprived due to insomnia

Percentage of workers 65 and older with insomnia

Percentage of working men with insomnia

Percentage of working women with insomnia

Percentage of insomnia among workers with a high school education

Percentage of insomnia among workers who dropped out of high school

Percentage of insomnia among workers with a college degree

Percentage of insomniacs on medication or in behavioral therapy

Annual cost of sleep-aid medication

Annual cost of sleep behavior modification therapy

$40 billion
Amount Americans spend on coffee each year

Number of full-time employees surveyed for the study

Sources: USA Today/HealthDay, Los Angeles Times, CNN/, WebMD, TIME, EurekAlert, Specialty Coffee Retailer