When going through the profiles of the top users you can find things like:
And the same occurs for Darin Dimitrov (ranked #2), BalusC (#3) and all the way until Daniel Roseman (#46): they all get a text "top 0.01% overall". This is not bad per-se, so we get a good vision of someone being among the best users.
However, in small sites, the top user from all time gets a "top 0.28% overall":
This does not give much information as a number, and rarely makes us think that it is the person with the more reputation overall.
For this, I suggest changing the text to something more meaningful for top users like:
top #1 user overall
We could argue that the site is not about competition itself. However, the fact that we have such rankings, as well as tag top users, makes me think that such change will give better content than what those "top XX% overall" are currently giving.