Isn't this supposed to be:

@keys = keys{%hash};
foreach $key (@keys)
{
   $value = $hash{$key};    # notice $ versus % here
   push(@values, $value);
}
sort(@values);
print "@values\n";
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Otherwise, I think you get an error such as:

Can't use subscript on private hash at foo.pl line 123, near "$key}"
(Did you mean $ or @ instead of %?)
BEGIN not safe after errors--compilation aborted at foo.pl line 123.
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