 140 (or about 10.38% of the population) belonged to no church, are agnostic or atheist, and 44 individuals (or about 3.26% of the population) did not answer the question.In Ziefen about 507 or (37.6%) of the population have completed non-mandatory upper secondary education, and 173 or (12.8%) have completed additional higher education (either university or a "Fachhochschule").Of the 173 who completed tertiary schooling, 69.9% were Swiss men, 21.4% were Swiss women, 5.8% were non-Swiss men and 2.9% were non-Swiss women.