In the late 1980s Bulgaria had almost 9 million inhabitants; the 2021 census counted just 6.52 million. Two forces are at work: large-scale emigration after the fall of communism, especially to Western Europe, and natural decline, with far more deaths than births. Between 2011 and 2021 alone, the country lost 11.5% of its population. Bulgaria is among the fastest-shrinking countries in the world.
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.