Line up every human from youngest to oldest and the person in the middle would be around 30, up from about 22 in the early 1970s. Yet the gaps are huge: the median age is under 17 in several Sahel countries and close to 50 in Japan. Two demographic worlds share the same planet.
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.