"Non-profit institutions in the satellite account are classified by primary area of activity according to the International Classification of Non-profit Organizations (ICNPO). It is the classification system recommended in the United Nations (UN) Handbook on Non-profit Institutions in the System of National Accounts. The ICNPO system groups organizations into 12 major activity groups, including a catch-all 'not elsewhere classified' category. These 12 major activity groups are further divided into 24 subgroups. Satellite account estimates are published at the major group level."