Roughly 42% of U.S. assisted living residents has Alzheimer’s and other types of dementia, and about 70% are women, according to a newly published data brief.

Drawing on data from the 2010 National Survey of Residential Care Facilities, researchers at the Centers for Disease Control and Prevention looked at data from a representative sample of 2,302 facilities — the first survey ever of such facilities. The median length of stay was approximately 22 months with a mean total charge of $3,165 per month. Medicaid paid for about 19% for at least some services, according to the report.

The report also takes a look at how many assisted living residents need assistance with activities of daily living. About 38% needed help with three or more ADLs, and only a fraction had never been diagnosed with a common chronic condition.

Click here to read the CDC’s National Center for Health Statistics assisted living data brief.