The association has existed for over 80 years.[2] Its holds two national early childhood conferences per year, the NAEYC Annual Conference & Expo and the NAEYC National Institute for Early Childhood Professional Development.[3] The NAEYC Annual Conference & Expo is the largest early childhood education conference in the world.[3] The association publishes periodicals, books, professional development materials, and resources, all of which relate to the education of young children. The association is also active in public policy work. The association is well known for accrediting high-quality child care/preschool centers, and more than 10,000 centers, programs and schools have earned NAEYC Accreditation.