Question: The stadium used for the EFL championship in the town that lies at the confluence of the River Brent and the Thames was built in what year ?

text: EFL Championship
Current members
LondonBarnsleyBirmingham CityBlackburn RoversBristol CityCardiff CityDerby CountyHuddersfield TownHull CityLeeds UnitedLuton TownMiddlesbroughNottingham ForestPreston North EndReadingSheffield WednesdayStoke CitySwansea CityWest Bromwich AlbionWigan AthleticLondon teamsBrentfordCharlton AthleticFulhamMillwallQueens Park Rangers Locations of the 2018–19 Football League Championship teams BrentfordCharlton AthleticFulhamMillwallQueens Park Rangers Greater London Championship football clubs The following 24 clubs competed in the EFL Championship during the 2019–20 season .
The English Football League Championship (often referred to as the Championship for short or the Sky Bet Championship for sponsorship reasons) is the highest division of the English Football League (EFL) and second-highest overall in the English football league system after the Premier League. The league is contested by 24 clubs. Each season, the two top-finishing teams in the Championship are automatically promoted to the Premier League. The teams that finish the season in 3rd to 6th place enter a playoff tournament, with the winner also gaining promotion to the Premier League. The three lowest-finishing teams in the Championship are relegated to League One. The Football League Championship, which was introduced for the 2004-05 season, was previously known as the Football League First Division (1992-2004), and before that as the Football League Second Division (1892-1992). The winners of the Championship receive the Football League Championship trophy, the same trophy as the old First Division champions were handed prior to the Premier League's inception in 1992. Similar to other divisions of professional English football, Welsh clubs can be part of the division, making it a cross-border league. The Championship is the wealthiest non-top flight football division in the world and the eighth richest division in Europe. With an average match attendance for the 2018-19 season of 20,181, the Championship had the highest per-match attendance of any secondary league in the world, with only nine top-flight leagues known to have higher attendance figures. Barnsley have spent more seasons at the second level of English football than any other team and on 3 January 2011 became the first club to achieve 1,000 wins in the second level of English football with a 2-1 home victory over Coventry City. Barnsley are also the first club to play 3,000 games in second-level league football (W1028, D747, L1224).
Club Finishing position last season Location Stadium Capacity
Barnsley 2nd in League One ( promoted ) Barnsley Oakwell 23,287
Birmingham City 17th Bordesley St Andrew 's 30,016
Blackburn Rovers 15th Blackburn Ewood Park 31,367
Brentford 11th London ( Brentford ) Griffin Park 12,763
Bristol City 8th Bristol Ashton Gate 27,000
Cardiff City 18th in Premier League ( relegated ) Cardiff Cardiff City Stadium 33,316
Charlton Athletic 3rd in League One ( promoted via play-offs ) London ( Charlton ) The Valley 27,111
Derby County 6th Derby Pride Park Stadium 33,597
Fulham 19th in Premier League ( relegated ) London ( Fulham ) Craven Cottage 19,000
Huddersfield Town 20th in Premier League ( relegated ) Huddersfield Kirklees Stadium 24,121
Hull City 13th Kingston upon Hull KCOM Stadium 25,404
Leeds United 3rd Leeds Elland Road 37,900
Luton Town 1st in League One ( promoted ) Luton Kenilworth Road 10,356
Middlesbrough 7th Middlesbrough Riverside Stadium 34,742
Millwall 21st London ( South Bermondsey ) The Den 20,146
Nottingham Forest 9th Nottingham City Ground 30,576
Preston North End 14th Preston Deepdale 23,408
Queens Park Rangers 19th London ( Shepherd 's Bush ) Loftus Road 18,360
Reading 20th Reading Madejski Stadium 24,200
Sheffield Wednesday 12th Sheffield Hillsborough 39,732