The Center for Disease Control and Prevention (CDC) released a unique study that measured income versus sleep time for families in both metro and non-metro areas. A national health survey conducted in 2013 showed that lower income households were more likely to get less than six hours of sleep per night than higher income households in the same area.

In short, CDC data suggests that the poor sleep less.

The most telling data comparison is that roughly two-thirds of families living under the poverty line ( $23,550 for a family of four in 2013) reported getting more than than six hours per night, while about three-quarters of people with incomes at 400% of the poverty level ($94,200 for a family of four) reported getting the same amount.

Sleep specialists say seven hours is the magic snooze number, but that also depends on your age group. The youngest and oldest need to sleep more than others. Either way, not enough people from either income bracket are getting enough sleep.

Why those who are financially struggling report less z-time is unclear.

The Washington Post suggests that perhaps because a high number of low-income American workers are holding down multiple low-wage jobs just to get by. Another study from last year focusing on “short-sleepers” — i.e. those getting less than six hours — corroborates the point. Most short-sleepers reported trading precious pillow time for those extra hours at work.