Please answer the following question: I know that the answer to the question "How does IAH rank in non stop flights?" is in "The primary city airport is George Bush Intercontinental Airport (IAH), the tenth-busiest in the United States for total passengers, and twenty eighth-busiest worldwide. Bush Intercontinental currently ranks fourth in the United States for non-stop domestic and international service with 182 destinations. In 2006, the United States Department of Transportation named IAH the fastest-growing of the top ten airports in the United States. The Houston Air Route Traffic Control Center stands on the George Bush Intercontinental Airport grounds.". Can you tell me what it is?
Answer:
fourth in the United States