According to the World Bank, about 75% of humanity lives in middle-income countries, neither rich nor poor. The picture of a world split in two, inherited from the 1960s, no longer fits the data: statistician Hans Rosling proposed four income levels instead, with most people in the two middle ones. Many of yesterday's 'developing countries' are now middle-income economies.
That's the estimate from a WHO-led study published in The Lancet in 2024, covering the half-century since the Expanded Programme on Immunization was launched in 1974. It works out to about six lives saved every minute, mostly infants. The measles vaccine alone accounts for around 60% of those lives.
According to the World Gold Council, about 216,000 tonnes of gold have been mined in all of human history. Because gold is so dense (19.3 tonnes per cubic metre), it would fit in a cube about 22 metres on each side, roughly the height of a seven-storey building. Strikingly, about two-thirds of it has been mined since 1950.