Queen Elizabeth has been in power so long, 4 out of 5 UK residents weren't alive when she ascended the throne

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Catherine, Duchess of Cambridge and Queen Elizabeth II.

Queen Elizabeth II has ruled for so long that most people in the United Kingdom have never known another monarch.

She became queen when her father, King George VI, died on February 6, 1952 (though her official coronation was on June 2, 1953).

During her reign, she has outlasted 14 British prime ministers and 12 (soon to be 13) US presidents.

The Queen is 90 years old, and a heavy cold kept her from regular appearances on Christmas and New Year's. When she dies, life will turn upside down for Brits, and many others who admire her from across the globe.

The impact will be even deeper because 81% of UK residents weren't alive when Queen Elizabeth ascended the throne.

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According to the UK Office for National Statistics, only 12 million UK residents were alive when King George was on the throne in 1952. That's only 19% of the UK's population of 65 million.

Since the most recent UK census data was from 2014, we used age-specific death rates to calculate how many Brits who were over 63 in 2014 would likely still be alive today.

This remarkable fact is a testament to Queen Elizabeth's stamina as Britain's longest reigning monarch.