More than half the people who would benefit from a Medicaid expansion in Missouri are workers who cannot afford health insurance but earn too much to qualify for assistance under current rules, an advocacy organization reported in a news release Thursday.

More than 300,000 uninsured Missourians would qualify for Medicaid under a proposed expansion, according to a study by Families USA, a not-for-profit organization that advocates for health care consumers.

The expansion -- which the federal government would fund completely through 2016 before dropping to 90 percent by 2020 -- would provide insurance to families earning up to 138 percent of the federal poverty level, which in 2014 is $27,310 for a family of three, the news release stated.

Under current rules, families without dependent children and families earning more than $4,750 a year are ineligible for Medicaid, the release stated.

According to the report, workers who would benefit from the expansion include those working in food service, sales, cleaning and maintenance, office and administrative support jobs, transportation, construction, personal care, health care support and other professions.

Another 20 percent of the newly eligible adults would be those deemed "not in the workforce" -- students, nonworking spouses, people with disabilities and those who have left the workforce -- with the remaining 20 percent unemployed, the release stated.