This means how high you are in the rankings in the segment times driven. If there are 100 people, including you, who have cycled a certain segment and you have the 10th fastest time, you are in the "top 10%". If you have the 3rd fastest time, in this case it is "top 3%".

Especially in segments that thousands of people have cycled, such as the Alpe d'Huez or the like, you have an idea of where you stand in the list.

That was not the question. The question was why strava doesn't show an actual number and just says "top x%" instead of say: "top 5%"

Only subscribers see the actual number.

Because there are segments with 15,000 athletes.  It’s a convenient and interesting To know your absolute rank as well as your percentile.  Something you can’t always calculate easily….  (Read on…)

Think about this…. What if there’s a 20 way tie for first, 115 people in second place, 300 people in third place, and another 650 with lower rankings.  If you were one of the people in third place, what percentile would you be?

(see, not so simple)

gggempire, 

when you say “strava doesn't show an actual number”, what do you mean by “actual number“?  Did you mean to say total athletes for that segment?  If so, they actually do post that number, but you have to scroll way down to the bottom to see it. 

Ah ok thank you. I figured it was some paywall thing. Thanks for the answer!!!

No wonder such a simple concept created so much confusion.
Thanks for clarifying Jan_Mantau