I think Statistics::Lite could help you, it's pure perl and easy to use.
Else, a simple sort algorithm should help you, if you have your data stored in a hash like

# untested...
%list = (
   RUBYKAT=>15.97 ,
   SAPER=>15.78 ,
   PETDANCE=>15.5 ,
   AMBS=>15.5 ,
   BARBIE=>15.45 ,
);
sub sortDesc {
   $list{$b} <=> $list{$a};
}
foreach $key (sort sortDesc (keys(%list))) {
   print "$list{$key} \t $key \n";
}
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but i don't think there is a specific cpan module available to this.
anyway, i would not use an array of arrays for this.