$somehash{foo}{bar}{baz}++;
  $somehash{quux}{wibble}{42}++;

  foreach $x (keys %somehash) {
     foreach $y (keys %{$somehash{$x}}) {
        foreach $z (keys %{$somehash{$x}{$y}}) {
            print "There were $somehash{$x}{$y}{$z} ".
              "occurrances of $x,$y,$z\n";
         }
     }
  }