title: Spooks (TV series)
context: Spooks (known as MI-5 in some countries) is a British television drama series that originally aired on BBC One from 13 May 2002 to 23 October 2011, consisting of 10 series. The title is a popular colloquialism for spies, and the series follows the work of a group of MI5 officers based at the service's Thames House headquarters, in a highly secure suite of offices known as The Grid. It is notable for various stylistic touches, and its use of popular guest actors. In the United States, the show is broadcast under the title MI-5. In Canada, the programme originally aired as MI5 but now airs on BBC Canada as Spooks.
question: How many series of Spooks have been released?
answers: 10