 Though the organization maintained 20-25,000 people in its frontline units, due to overall growth of the Nationalist army the percentage of requetés fell to 9% in April 1937, to 5% in January 1938, and to 3% by the end of the war.They were grouped in Carlist-only infantry battalions named tercios.There are some 40 of them known, though many were under strength and short-lived, later to be merged into other units; only about 15 operated throughout most of the war.