(Associated Press) – Parents are opting out of school vaccinations at the highest rate ever.

Last school year, that amounted to 3% of U.S. children entering kindergarten.

The highest rate was 12% in Idaho, where a change in state law a few years ago made it easier to opt out.

All states require students to have certain vaccines to attend public school, and often private school and day care.

Exemptions are given for medical reasons, and sometimes for religious beliefs or personal reasons.

Most states saw an increase in exemption rates last year