ATLANTA, Ga. (CNN) — More parents and guardians in the U.S. are getting vaccine exemptions for their kindergarten-age kids. The CDC says there has been a small increase in vaccine exemption rates among kindergartners.

The findings were published in the CDC’s Morbidity and Mortality Weekly Report Thursday. It shows that rates of young children not receiving vaccinations against certain diseases, including measles, has steadily gone up in recent years.

For the 2018-2019 school year, the national percentage of kindergartners with an exemption from one or more required vaccines was 2.5%.

That’s a slight increase from 2.3% during the previous school year and 2.1% the year prior to that.