[Getty Images]Newcastle have finished above Tottenham in the Premier League in three of the past four seasons. However, Spurs are still a long way clear of the Magpies in the revenue table thanks to substantial off-field income streams, which have offset difficult league campaigns.In the respective clubs' most recent financial accounts, the Londoners generated £230m more in revenue than Newcastle.Spurs are now looking to make the most of such headroom by raising their salary ceiling.In an