Iceland, Isreal, Gibraltar, and Singapore, are all over 90% vaccinated, and all have higher rates than we do. In Israel, 80% of all reported deaths are now among those fully vaccinated.
In the U.S., the CDC does not record a breakthrough case unless the person is hospitalized or dies, so we don't know how many of the people who test positive are fully vaccinated. We only know if they are hospitalized or die.