Answer based on context:

On 17 January 2011, it was announced that Motörhead would be part of the Sonisphere Festival in Knebworth. In August 2011, they headlined the Brutal Assault open-air festival in the Czech Republic. On 2 March 2011 Motörhead performed on Late Night with Jimmy Fallon. On 9 July 2011, former guitarist Würzel died of a heart attack. In celebration of 35 years touring, in late 2011 the band released the live DVD The Wörld Is Ours - Vol 1 - Everywhere Further Than Everyplace Else, including performances at the O2 Apollo Manchester, Best Buy Theater, New York City and Teatro Caupolicán, Santiago de Chile. On 19 December 2011, it was announced that Motörhead would play at the German festivals Rock am Ring and Rock im Park in Nürburgring and Nuremberg respectively in June 2012. On 12 January 2012, it was announced that Motörhead were touring the US and Canada in early 2012, along with three other metal bands Megadeth, Volbeat and Lacuna Coil. The Gigantour took place from 26 January to 28 February 2012, but Motörhead missed the final four shows because Lemmy had a combination of an upper respiratory viral infection and voice strain, resulting in severe laryngitis. Lemmy wrote on Facebook, "Im giving my voice a good rest", hoping he would recover soon to play at the Mayhem Festival, which was held from 30 June to 5 August 2012. Motörhead also took part on 23 June in the Rock-A-Field Luxembourg Open Air Festival in Roeser.

How many performances for Motörhead were announced in 2011?
4