You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Guinea-Bissau

Context:
João Bernardo "Nino" Vieira was elected in 2005 as President of Guinea-Bissau as an independent, being declared winner of the second round by the CNE (Comité Nacional de Eleições). Vieira returned to power in 2005 six years after being ousted from office during a civil war. Previously, he held power for 19 years after taking power in 1980 in a bloodless coup. In that action, he toppled the government of Luís Cabral.

Question:
How long was it since Vieira had held the office of president?

six years