Question: International Consolidated Airlines Group, S.A., often shortened to IAG, is an Anglo-Spanish multinational airline holding company,  it was formed in January of which year, after a merger agreement between British Airways and Iberia, the flag carrier airlines of the United Kingdom and Spain respectively?
Sentence (from "Iberia (airline)"): Based in Madrid, it operates an international network of services from its main base of Madrid-Barajas Airport.
Relevant evidence: No