foo     73
bar     35
word    27
blah    23
...

##</code><code>##

for(@files){
  open IN, $_;
  while(<IN>){
    /^(.*)\t(.*)$/;
    $f{$1}+=$2;
  }
}
@p=values %f;
@q=keys %f;
@i=sort{$p[$b]<=>$p[$a]} 0..$#p;
open OUT, '>', $outpath;
for(@i){
  print OUT "$q[$_]\t$p[$_]\n";
}