Another day, another study on the benefits of the Affordable Care Act and the gains we risk losing if the Trump administration continues to undercut the law’s patient protections.

This time it’s a study on health coverage by occupation, showing that while insurance rates have increased overall for working adults, there’s still a ways to go in closing coverage gaps between occupations. The new findings, published this week in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report, are based on 2013 and 2014 data from the agency’s Behavioral Risk Factor Surveillance System. Researchers found that between 2013 and 2014, the uninsured prevalence among U.S. workers ages 18 to 64 declined by 21 percent, from 16 percent to 12.7 percent.

However, that prevalence shifts considerably among occupations, with workers in some of the lowest-paying jobs also experiencing some of highest rates of going without health coverage. For instance, prevalence of being uninsured ranged from 3.6 percent in architecture and engineering jobs and less than 3 percent among community and social services workers to nearly 38 percent among workers in the farming, fishing and forestry industries and 37 percent in cleaning and maintenance jobs.

In 2014, food prep and restaurant workers had an uninsured rate of more than 35 percent, and construction and extraction workers reported an uninsured rate of about 29 percent. That same year, according to the study, uninsured rates topped 20 percent among workers who spoke Spanish, who had less than a high school education, who lived in a household with an annual income of less than $35,000, were self-employed and were of Hispanic ethnicity.

Not surprisingly, Medicaid made a difference in ensuring more workers had access to affordable health care. The study found that in both 2013 and 2014, the rate of uninsured workers was lower in states that expanded Medicaid eligibility, compared to states that rejected Medicaid expansion. Uninsurance among working adults declined by 23 percent in states that expanded their Medicaid programs, versus 9 percent in states that didn’t expand.

Researchers said the overall drop in working adults going without health coverage is consistent with national data also showing big drops since ACA implementation — between 2013 and 2014, the overall adult uninsurance rate in America dropped from more than 20 percent to just above 16 percent, and the most recent Census data show the nation’s uninsured rate was down to 8.8 percent as of 2016. (Though as we reported last month, America’s overall uninsured rate has begun to inch back up under the Trump administration, and the latest Census figures show employer-sponsored coverage has stayed stable in recent years after consistently declining in the years preceding the ACA. Neither bodes well for closing worker coverage gaps if the ACA continues to be weakened.)

The CDC researchers write: “Because some workplace conditions and health outcomes vary by industry or occupation, workers might rely on health insurance for treatment of work-related injuries or illnesses, and health insurance coverage can influence health status as well as the ability to remain employed, identifying factors affecting differences in insurance rates by occupation might help to target interventions to reduce health disparities among U.S. workers.”

For a copy of the new insurance study, visit MMWR.