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:
Oklahoma_City

Context:
According to the Oklahoma City Chamber of Commerce, the metropolitan area's economic output grew by 33 percent between 2001 and 2005 due chiefly to economic diversification. Its gross metropolitan product was $43.1 billion in 2005 and grew to $61.1 billion in 2009.

Question:
What was Oklahoma cities gross metropolitan product in 2009?

$61.1 billion