One quarter of the bitcoin supply was mined, which is just one quarter of the eventual total of nearly 21 million.

The milestone of one quarter of the Bitcoin supply being mined was a significant event in the cryptocurrency’s history. This meant that approximately 5.25 million Bitcoins had been generated, marking just over one-quarter of the eventual total supply limit of 21 million. The event happened in block 105,000.

The mining reward halving events, which occur approximately every four years, play a crucial role in the controlled supply distribution of Bitcoin, ensuring that the total supply will be mined over a long period, with the last Bitcoin expected to be mined around the year 2140.