frequency

#!/usr/bin/perl
use strict;
use warnings;
use Text::CSV q(csv);
use feature q(say);

my $csv = csv(in => \*ARGV, headers => [qw(group name item)]);
my $count = [];
for my $c (@$csv) {
  my $d;
  for (@$count) {
    if ($_->{name} eq $c->{name}) {
      $d = $_;
      last;
    }
  }
  push @$count, ($d = { name => $c->{name} }) unless $d;
  $d->{all}++;
  $d->{hit} = 0 unless $d->{hit};
  $d->{hit}++ if $c->{group} <= 3;
}
$, = ',';
for (sort {$a->{name} cmp $b->{name}} @$count) {
  say $_->{name}, $_->{hit} / $_->{all} * 100;
}