I want to know the answer to the following question:
How much did oil and gas exploration and production make up Houston's gross product?
All the background I'm provided with is that "The Houston–The Woodlands–Sugar Land MSA's gross domestic product (GDP) in 2012 was $489 billion, making it the fourth-largest of any metropolitan area in the United States and larger than Austria's, Venezuela's, or South Africa's GDP.". Is that enough to answer the question?