Foreign footballers in the English Premiership

Arsenal were the victors of last night's match in come-back against Aston Villa. But who was it all up to? Two goals by Robin Van Persie, and one by Theo Walcott. And the squad behind them were from the Czech Republic, Cameroon, Poland... With a team who 82% from abroad, this got us thinking how dependent are English teams on foreign talent? And what is the impact of this?