Bill Gates says he has given away billions, but has more to give

Maxine Collins/BBCIt's towards the end of our interview that Bill Gates reveals new numbers on how much his charitable Foundation has now spent in its efforts to combat preventable diseases and reduce poverty. "I've given over 100 billion," he says, "but I still have more to give."That's dollars, just to clarify, worth about £80bn.It's roughly equivalent to the size of the Bulgarian economy or the cost of…