Sunday, October 18, 2026 · Played it? Here's how rare each one really was.
Pooled from 34 studies, 1966–2016.
1 in 1.8 people 54.9%
A 2016 meta-analysis estimated 55% of people have had at least one lucid dream in their lifetime.
Fun fact: More than half of us have done it. About 23% have them at least once a month, roughly 7 people in a class of 30.
Any two of them, any day of the year.
1 in 2 groups of 23 50.7%
It's a coin flip, about 50.7%. Twenty-three people make 253 pairs, and each pair is another chance to match. This assumes 365 equally likely birthdays.
Fun fact: It feels like you'd need about 183 people (half of 365), but 23 already gets you there. With 70 people it's 99.9%.
Source: Math: the birthday problem
All summits 1922 to December 2025.
1 in 2.2 summits 45.0%
There were 13,737 summits by 7,563 different people through 2025, so 6,174 summits (45%) were repeats.
Fun fact: Nearly half of all summits are repeat trips. On average, each person who has stood on top has done it about 1.8 times.
Source: Alan Arnette, Everest by the Numbers 2026, from the Himalayan Database
US population.
1 in about 14 people 7.00%
The American Red Cross says 7% of the US population has O negative blood. O positive is the most common at 38%.
Fun fact: O negative is the universal blood type that can go to anyone, which is why it's often the first to run out in a shortage.
Source: American Red Cross
All five dice must show 6.
1 in 7,776 rolls 0.013%
Each die has a 1 in 6 chance, so five in a row is 6 × 6 × 6 × 6 × 6.
Fun fact: It's 6 times harder than any five of a kind, because now the number has to be 6 too. Rolling every 10 seconds, you'd wait about 21 hours.
Source: Math: 6⁵ = 7,776