Question: What is the domestic football capacity of the stadium which hosted the 2011 Conference Premier play-off Final ?

Context articles: 2015 Conference Premier play-off Final
2011 Conference Premier play-off Final
2009 Conference Premier play-off Final
2014 Conference Premier play-off Final
2012 Conference Premier play-off Final
2013 Conference Premier play-off Final
Salisbury City F.C.
2010 Conference Premier play-off Final
2008 Conference Premier play-off Final
City of Manchester Stadium

The 2015 Conference Premier play-off Final, known as the 2015 Vanarama Conference Promotion Final for sponsorship reasons, was a football match between Bristol Rovers and Grimsby Town played on 17 May 2015 at Wembley Stadium in London.
 It was the thirteenth Conference Premier play-off Final, the eighth to be played at Wembley and the first to feature either side.
The 2011 Conference Premier play-off Final, known as the 2011 Blue Square Bet Premier play-off Final for sponsorship purposes, was a football match between AFC Wimbledon and Luton Town on 21 May 2011 at the City of Manchester Stadium in Manchester.
 It was the ninth Conference Premier play-off Final and the first to be played at the City of Manchester Stadium.
 AFC Wimbledon won the match 4–3 in a penalty shoot-out following a 0–0 draw after extra time to secure promotion to Football League Two, thus entering the Football League for the first time in the club's nine-year history.
The 2009 Conference Premier play-off Final, known as the 2009 Blue Square Premier play-off Final for sponsorship purposes, was a football match between Cambridge United and Torquay United on 17 May 2009 at Wembley Stadium in London.
 It was the seventh Conference Premier play-off Final and the third to be played at Wembley.
The 2014 Conference Premier play-off Final, known as the 2014 Skrill Premier play-off Final for sponsorship reasons, was a football match between Cambridge United and Gateshead on 18 May 2014 at Wembley Stadium in London.
 It was the twelfth Conference Premier play-off Final.
The 2012 Conference Premier play-off Final, known as the 2012 Blue Square Bet Premier play-off Final for sponsorship purposes, was a football match between Luton Town and York City on 20 May 2012 at Wembley Stadium in London.
 It was the tenth Conference Premier play-off Final and the first to be played at Wembley since 2010.
 York won the match 2–1, coming from behind after conceding to Luton in the second minute to secure promotion to Football League Two, re-entering the Football League after an eight-year absence.
The 2013 Conference Premier play-off Final, known as the 2013 Blue Square Bet Premier play-off Final for sponsorship purposes, was a football match between Wrexham and Newport County on 5 May 2013 at Wembley Stadium in London.
 It was the eleventh Conference Premier play-off Final and the first ever Wembley Final to feature two teams from Wales.
Salisbury City Football Club was an English football club based in Salisbury, Wiltshire.
 They were formed in 1947 and played at The Raymond McEnhill Stadium.
 Salisbury had gained back-to-back promotions in recent years, first to the Conference South in the 2005–06 season by finishing top of the Southern League Premier Division, followed by winning the play-off final in the 2006–07 season to participate in the Conference Premier in 2007–08.
 They played the 2010–11 season in the Southern League Premier Division after being relegated from the Conference Premier at the end of the 2009–10 season, but managed to win promotion to the Conference South for the 2011–12 season in the first season following their relegation.
 The club spent two seasons in the Conference South before winning promotion to the Conference Premier via the play-offs in the 2012–13 season.
 In 2014, the club were removed from the Football Conference after failing to pay debts.
 The club has reformed as Salisbury F.C. for the 2015–16 season.
The 2010 Conference Premier play-off Final, known as the 2010 Blue Square Premier play-off Final for sponsorship purposes, was a football match between Oxford United and York City on 16 May 2010 at Wembley Stadium in London.
 It was the eighth Conference Premier play-off Final and the fourth to be played at Wembley.
 The 2010 Final set a new Conference Premier play-off Final attendance record of 42,669 (158 more than the existing record set by Cambridge United and Exeter City two seasons before) with ticket sales suggesting Oxford United brought over 33,000 of these.
The 2008 Conference Premier play-off Final, known as the 2008 Blue Square Premier play-off Final for sponsorship purposes, took place on 18 May 2008 at Wembley Stadium, London.
 It was contested between Cambridge United and Exeter City, with Exeter winning 1–0 and securing their return to the Football League after five years' absence.
The City of Manchester Stadium in Manchester, England, also known as the Etihad Stadium for sponsorship reasons, is the home ground of Manchester City Football Club and, with a domestic football capacity of 55,097, the fourth-largest in the Premier League and eighth-largest in the United Kingdom.