It's zero percent of the universe when you take into account the finite amount of space we can see over the infinite amount of space there actually is.

It's still pretty damned amazing for an infinitesimally small part of the universe.

If by an "amount of space there actually is" you mean observable Universe, then we can see a pretty darn big chunk of it, considering that the space is mostly empty. Also, correct me if I'm wrong, but there is no way of knowing if there is an infinite space outside an observable Universe.

As far as I know, the current working model of the universe presumes an infinitely large universe. That's what all the math seems to indicate. Obviously, since the rest is not observable, nor can we ever interact with it, proving this in a tangible way is not possible.

It's just that we can only see and interact with a finite portion of this universe, and sadly, over time this portion will shrink in relative terms.

In the distant past, more of the actual universe was visible. The distances between galactic clusters was smaller.

In the vastly distant future, our galaxy might be the only one visible. The rest of space will simply be empty, light stretched out so much that it's nothing more than faint background noise.