The number of pupils per teacher in the world's primary schools varies from about a dozen in Norway or Sweden to over 90 in the Central African Republic. Generally, class sizes in the developing world are at least two to three times larger than classes in industrialized nations. A more relevant measure is school-age-children-per-teacher. For instance, if all the children in Ethiopia went to school the number of primary school pupils per teacher would rise from an average of 30 to 119.