Five years after Amazon.com raised wages to $15 an hour, half of warehouse workers surveyed by researchers say they struggle to afford enough food or a place to live.

The national study, published Wednesday by the University of Illinois Chicago’s Center for Urban Economic Development, asked U.S. employees about their economic wellbeing, including whether they’d skipped meals, went hungry, or were worried about being able to make rent or mortgage payments.

About 53% of respondents reported that they’d experienced one or more forms of food insecurity in the prior three months, and 48% experienced one or more forms of housing insecurity. The researchers found that workers who said they took unpaid time off after getting hurt on the job were more likely to report trouble paying their bills.