  Let $G$ be a finite group, $A$ a unital separable finite simple nuclear
C*-algebra, and $\alpha$ an action of $G$ on $A$. Assume that $A$ absorbs the
Jiang-Su algebra $\mathcal{Z}$, the extremal boundary of the trace space of $A$
is compact and finite dimensional and that $\alpha$ fixes any tracial state of
$A$. Then tsr$(A \rtimes_\alpha G) = 1$. In particular, when $A$ has a unique
tracial state, we conclude it without above conditons on a tracial state space
of $A$.
