use warnings;
use strict;
##</code><code>##

  my %type;
     @type{qw(AB AC AD AE FG)} = (0) x 5;

##</code><code>##

##then you have something like this:
$VAR1 = {
          'AC' => 0,
          'AE' => 0,
          'FG' => 0,
          'AB' => 0,
          'AD' => 0
        };


##</code><code>##

   while(...){
    ...
    $type{$_}++;  ## increasing the counting as you see needed string
    ...
  }