Let $T\subset G$ be the set of all torsion elements in a finitely generated infinite group $G$, and let $B_n\subset G$ be the closed ball of radius $n$ around $1$ w.r.t. to the word metric for some choice of a finite generating set. Consider the upper density
$$
t(G)=\limsup_{n\rightarrow\infty}\frac{|B_n\cap T|}{|B_n|}.
$$
The extreme values $t=0$ and $t=1$ are attained trivially for (torsion-)free groups and [finitely generated infinite torsion groups][1] respectively. Slightly less obvious is that $t(G\ast H)=0$ whenever $t(G)=0$ and $H$ is finite, which one can show using [Kurosh's Theorem][2].

> **Questions**
> 
>  1. Is the value of $t$ idependent of the choice of a generating set for $G$?
>  2. Is the $\limsup$ always a proper limit?
>  3. What is known about the values $t\in[0,1]$ that occur?

  [1]: https://en.wikipedia.org/wiki/Burnside_problem
  [2]: https://en.wikipedia.org/wiki/Kurosh_subgroup_theorem