The number of individuals who remain entirely unvaccinated in America is small, estimated at approximately 1% or less of the American population.

Gowda C, Dempsey A (2013). The rise (and fall?) of parental vaccine hesitancy. Hum Vaccin Immunother 9(8): 1755–1762. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3906278/