The Clinton Global Initiative has this week seen a thousand of the world's richest, most famous and powerful people attend Bill Clinton’s event, each paying $15,000 (£7,400), money that goes to support worthy causes.

The event, now in its third year, raised more than $10bn in its first two years and this year the figure is likely to be surpassed; the opening day brought in several billions.

The event champions ’New Philanthropy’ and attracts celebrity philanthropists such as Brad Pitt, Angelina Jolie and Andre Agassi alongside politicians, former and current, including Tony Blair and Al Gore.

It is estimated that Americans gave $295bn in charitable donations in 2006. Americans give 2.1% of their GDP to charity, the highest rate of giving in the world. The UK comes second with 0.73%.