while(<FLATFILE>) {
  @stuff = split(/|/, $_);
  push(@cats, $stuff[0]);
  ## Do other stuff with @cats or @stuff, and then:
  $subcat{$stuff[1]}++;
}

## This creates a hash (%subcat) in which the keys are the subcategori
+es, 
## and the values are the total of each one.
## So, to output a pretty list:

for $x (sort keys %subcat) {
  print "$x ($subcat{$x})\n";
}
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This will display them in alphabetical order. From the looks of your data, this is probably desired.