How much solid matter is in the observable Universe? I want to know the volumetric ratio of empty space to planets, stars, and all other solid matter combined. Not considering any dark matter, dark energy, or black holes.
For example, you can say X percent of the observable space is just empty space. The remainings are comets, stars, planets, and so on.
Edit:

I meant solid as in all the things that are not gas.
I know that space is not exactly empty, let's consider that empty means all other things except solid.
I'm not looking for exact numbers but just an estimation.
Any non-star is negligible, their volume is practically zero.
Most matter in the Universe is gravitationally bound plasma, resulting that they do not have a well-specifiable volume, because their density continuously changes from the interstellar vacuum to many times of lead. But choosing a surface at any arbitrary point (for example, at 1 bar pressure) does not modify the result significantly (this is why we can say a radius for the Sun).
This source says that the estimated count of the stars in the visible Universe is $10^{21}$. This is obviously not very exact, there are probably better estimations which you substitute into this answer.
The majority of the stars in the Universe is a red dwarf. Their radius varies between 9% and 50% of the Sun, we get their geometric average, this is $\approx$ 21% of the Sun. Their volume is $\frac{4 \pi}{3}(0.21 \cdot 700000km)^3 \approx 1.37 \cdot 10^{16} km^3$.
Thus, the volume of all stars in the Universe is $\approx 1.37 \cdot 10^{37} km^3$.
The observable Universe is a sphere with the radius of 46billion light years.1 A light year is $\approx 9.5 \cdot 10^{12} km$. Thus, the volume of the observable Universe is $\frac{4 \pi}{3} (23 \cdot 10^{12} \cdot 9.5 \cdot 10^{12})^3 \approx 4.37 \cdot 10^{79} km^3$.
After a division, we get that
$$\frac{1.37 \cdot 10^{37}}{4.37 \cdot 10^{79}} \approx \underline{\underline{\frac{1}{3.2 \cdot 10^{42}}}}$$
part of the volume of the visible Universe is not empty space.
About 1 digit difference from the reality is possible due to the lack of not enough exact approximations.
1This is not the well-known and false 13.7 billion light years, which is the way what light could do since the Big Bang. The difference is coming from that meanwhile the Universe expanded, thus the stars we can see (as if they would be 13.7 billion ly far away) are now 46billion ly away. More details are on the wiki link.