I have completed a book called "Mobile Confederates from Shiloh to Spanish Fort the 21st Alabama". It is available from Heritage Books Inc. It includes the abstracted CSR's of the men that served. There were many foreign soldiers in the 21st Alabama but I have not calculated percentages. There was a company of Spanish and of French and a Irish group from a fire company plus a few misc. The Spanish and French Companies were transferred to a Louisiana Reg. after Battle of Shiloh. Arthur E. Green