  We study the evolution of a five-dimensional rotating black hole emitting
scalar field radiation via the Hawking process for arbitrary initial values of
the two rotation parameters $a$ and $b$. It is found that any such black hole
whose initial rotation parameters are both nonzero evolves toward an asymptotic
state
  $a/M^{1/2}=b/M^{1/2}={\rm const}(\neq 0)$, where this constant is independent
of the initial values of $a$ and $b$.
