STATISTICS has not, traditionally, been an exciting word. Its most common prefix is the word “dry”. Ask people what they think of statistics, or try to use some in an argument, and you will often get the quote attributed to Benjamin Disraeli that lists them alongside lies and damned lies. That is a shame: tables of figures may look dull, but they are a better guide to what is happening in the world than anything on television or in the press.

Hans Rosling had no time for the idea that statistics were boring. Armed with everything from a few Lego bricks and a pocketful of draughts pieces to snazzy, specially made computer graphics, he had a talent for using numbers to tell exciting stories. Not just exciting, but optimistic, too, for the tales those numbers told were of a world which, despite the headlines, was rapidly becoming a better place.

He knew what he was talking about. Besides being a statistician, he was also a doctor with experience in some of the world’s poorest corners. He did his PhD in Africa, studying a disease called konzo that strikes people whose diets include a lot of semi-processed cassava, which contains high levels of cyanide. But it was his flair for the dramatic that allowed him to share that expertise with other people.

It was a job that needed doing. By the 1990s he was teaching global health at the Karolinska Institute, in Stockholm. He found that his students—the cream of Sweden’s academic crop—had little idea about the world. When he gave them five pairs of countries and asked which of each pair had the higher rate of child mortality, the average number of correct answers was just 1.8. “Swedish students, in other words,” he said, “know…less about the world than a chimpanzee.” (The chimp, by choosing randomly, would score 2.5 out of five.) The same applied to his academic colleagues—who, as he pointed out with a twinkle in his eye, were responsible for handing out the Nobel prize for medicine.

He was a natural showman. In 2007 he finished a talk on global development with a demonstration of sword-swallowing, ingesting a Swedish-army bayonet live on stage. As his fame grew, he became a regular at gatherings of the great and the good, presenting talks at TED (a series of conferences supposed to give novel ideas an airing; his were much better than most) and attending Davos, an annual gathering of the masters of the universe in Switzerland.

His stock-in-trade was debunking gloomy stereotypes about poor countries and economic development. There were five surprising facts, for instance, that he loved to hammer home: population growth is slowing rapidly; the divide between the global rich and poor is blurring; humans are living much longer than 50 years ago; many more girls are getting an education; and the number of people in extreme poverty fell by a billion between 1980 and 2013.

Dr Rosling’s talent was to make those facts sing—to remind his audience that these dry-sounding numbers are, in fact, the sum total of billions of real lives that are better than they would have been half a century ago. His elevation annoyed some critics. Paul Ehrlich, a biologist who had, in the 1970s, predicted that hundreds of millions of people would starve by the end of that decade, accused him of being a Pollyanna. But it was hard to argue with his facts. Most simply celebrated him as a communicator of some happy truths.

Dr Rosling himself was sceptical about how much impact he had really made. People seemed to cling to their gloomy, wrong assumptions about the world. In 2013, in an interview with the Guardian, he reflected: “When we asked the Swedish population how many children are born per woman in Bangladesh, they still think it’s four to five.” In reality, the numbers have not been that high for 20 years. The current rate is 2.3—less than South Africa, and only slightly higher than New Zealand.