In fact, this figure originally derives from World Health Organisation and Unicef estimates, some dating back to the 1990s, from "sources of variable quality", about the prevalence of the practice in various African countries.
Many philanthropic organisations have already divested from fossil fuels, including the Rockefeller Brothers Fund whose wealth derives from Standard Oil, which went on to become ExxonMobil.
The union derives its legitimacy not from being a continent-wide democracy.
The erotic frisson of Christian Grey removing Anastasia's tampon derives not merely from the fact that, faced with her menstruation, Christian proceeds with his erotic education of young Anastasia; it's that he removes her tampon himself and then boinks her against the vanity.
Russia, which derives half its budget revenue from oil and gas, is already struggling with a collapse in the value of the rouble and an economy fast moving into recession.
BAE Systems, which makes fighter jets and submarines, now derives over half its turnover from after-sales service.
One, published in 2012 by James Stock of Harvard University (now a council member) and Mark Watson of Princeton University, derives America's potential growth rate from the long-term average of variables such as employment and productivity.
Portugal Telecom derives 46% of its revenues from the fast-growing Brazilian unit and its future growth depends on it.
Mr Obama now has a strategy; indeed, Mr Cameron helped the president build support for it during the recent NATO summit in Wales.The second worry derives from the wounding defeat the government suffered in the House of Commons last summer when it lost a vote to approve air strikes on Syria after President Bashar Assad's regime used chemical weapons.
The ayatollah has strongly condemned the shooting, but he derives much of his power from the right and is unwilling to alienate his supporters.Even were the constitution to be revised, many doubt whether Mr Khatami would go all out for profound change.
The book derives some authority from the authors' original research and benefits from the hours they spent sifting through the attics of descendants of other expedition members for personal diaries and photographs that were never part of the official record.
