Under the traditional Korean system, babies were 1 year old at birth and everyone added a year on 1 January. A child born on 31 December could therefore be 'two' the very next day. Since 28 June 2023, a law has required international age in official documents and contracts, making the whole population officially one or two years younger. A few rules, such as the legal drinking age and military service, still count by birth year.
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.