  In this paper we show that there is an infinite number of finite groups with
two relative subgroup commutativity degrees. Also, we indicate a sufficient
condition such that a finite group has at least three relative subgroup
commutativity degrees and we prove that $D_6$ is the only finite dihedral group
with two relative commutativity degrees. Finally, we study the density of the
set containing all subgroup commutativity degrees of finite groups.
