Let $$f(x) = \frac{x^2 - 4}{x^2 + 5}.$$ Find the average value of the horizontal asymptotes and the average value of the vertical asymptotes of $f(x)$. If there are no asymptotes of a given type, enter 'NONE'.

Horizontal asymptote(s): $y =$ Vertical asymptote(s): $x =$