Question: Walkinshaw Racing is an Australian motor racing team based in the Melbourne suburb of Clayton, Victoria, which at the 2011 Census, had a population of what?

Context paragraphs:
CAMS Rising Stars: CAMS Rising Stars is a motor racing team identity in which the Confederation of Australian Motor Sport assists the development of emerging young racing drivers.  The team competes in the Australian Formula Ford Championship.  There are two racing team which have been called CAMS Rising Stars.

Walkinshaw Performance: Walkinshaw Performance, is an automotive company, involved in motor racing and the production of high performance sporting cars for regular road use.  The company was founded by former racing driver, Scottish businessman, Tom Walkinshaw and is essentially a successor organisation to his previous automotive concern, Tom Walkinshaw Racing which was driven into bankruptcy by the failure of the Arrows Formula One team, then a part of TWR.  Walkinshaw Performance is now operated by Walkinshaw's son, Ryan.

Clayton, Victoria: Clayton is a suburb in Melbourne, Victoria, Australia, 19 km south-east of Melbourne's central business district.  Its local government area is the City of Monash.  At the 2011 Census, Clayton had a population of 15,543.

Tom Walkinshaw: Tom Walkinshaw (14 August 1946 – 12 December 2010) was a British racing car driver and the founder of the racing team Tom Walkinshaw Racing (TWR).  He was also involved in professional rugby union, as owner of Gloucester Rugby, and chairman of the team owners organisation for the Aviva Premiership.

Garry Rogers Motorsport: Garry Rogers Motorsport, also known as Wilson Security Racing GRM is an Australian motor racing team competing in the Supercars Championship.  The team is owned by retired racing driver Garry Rogers who began the team to further his own racing efforts.  Based in Melbourne, originally out of a Nissan dealership owned by Rogers, the team has competed in a variety of touring car series in Australia ranging from relatively modest Nissan production cars to Chevrolet NASCARs to building the GT specification Holden Monaro 427C.  The team won the Bathurst 1000 in 2000 and also won both of the Bathurst 24 Hour races which were held in 2002 and 2003.  In 2013 the team celebrated its 50th year in racing since Rogers made his debut.

Briggs Motor Sport: Briggs Motor Sport was an Australian motor racing team which has represented Queensland based businessman John Briggs in motor racing.  The team has competed in Sports Sedans, Australian GT, Formula Holden, and most notably as a touring car team competing in the V8 Supercar Championship Series.  The team last competed in historic motor racing and the Australian GT Championship but was folded at the end of the 2009 season.

Sieders Racing Team: Sieders Racing Team is a family-owned and -run Australian Touring Car, Sports Car and Truck Racing team that has competed in various Australian motor racing series.  The teams primary operation is racing a V8 Supercar Ford Falcon in the second-tier series, the Fujitsu V8 Supercar Series.

Scuderia Veloce: Scuderia Veloce was an Australian motor racing team founded by journalist racer David McKay that competed in many motor racing categories in the 1960s.  The team is regarded as the first professional motor racing operation in Australia.  The team was based in Wahroonga on Sydney's upper North Shore.

Walkinshaw Racing: Walkinshaw Racing is an Australian motor racing team based in the Melbourne suburb of Clayton.  The team currently fields two Holden VF Commodores in the Supercars Championship for James Courtney and Scott Pye, along with a Porsche 911 GT3-R in the Australian GT Championship.

Lansvale Racing Team: Lansvale Racing Team, also known as Lansvale Smash Repairs Racing was an Australian motor racing team that competed in Australian touring car racing between 1986 and 2003.

Supporting paragraphs: Walkinshaw Racing Clayton, Victoria
Answer: 15,543