The amount of money paid worldwide in bribes is between 1.5 trillion and 2 trillion dollars, or about 2% of the value of the world's economic output, the head of the International Monetary Fund (IMF) Christine Lagarde said Wednesday.

    Lagarde quoted the figure from recent IMF research in an open letter published one day before the start of an anti-corruption summit in London. She said the amount is an estimate of the total value of bribes paid annually in both developing and developed countries, according to the (dpa).

    Lagarde wrote that corruption - defined as an abuse of public office for private gain - "undermines trust in government and erodes the ethical standards of private citizens." While the direct economic costs of corruption are well known, "the indirect costs may be even more substantial and debilitating, leading to low growth and greater income inequality," Lagarde wrote.

    British Prime Minister David Cameron is hosting the global Anti-Corruption Summit on Thursday, providing global leaders their first opportunity to meet in the wake of the anonymously leaked Panama Papers.