the whole code:

#!usr/local/bin/perl

my $path='CustData.txt';
open(DATA, "<$path") || die "Couldn't open $path for reading: $!\n";

while (<DATA>)
{
    chomp;
    my ($id, $title, $surname, $forename, $sex, $dob, $vision) = split
+(/,/);
    $HoH{$id} = {'title' => $title, 'surname' => $surname, 'forename' 
+=> $forename, 'sex' => $sex, 'dob' => $dob, 'vision' => $vision,};
}
close(DATA);

$range1=1;
$range2=10;
$range3=1;
$range4=10;
$person_count=0;
print("Range\t10-20\t20-30\t30-40\t41-50\t51-60\t61-70\t71-80\t81-90\t
+91-99\n");
print("Count");
for ($counter=0;$counter<9;$counter++)
{
    $range3=$range3+10;
    $range4=$range4+10;
    print("\t  ".personCount($range3,$range4));
}
print("\n");


print("Percent\t");
for ($counter=0;$counter<9;$counter++)
{
    $range1=$range1+10;
    $range2=$range2+10;
    printf("  %.0f\t",(percent($range1,$range2)));
}
print("\n");

sub personCount
{
    ($x,$y) = @_;
    my ($vision_total,$person_count)=0;
    foreach my $id (sort keys %HoH)
    {
        if( ($HoH{$id}->{'vision'}>=$x) & ($HoH{$id}->{'vision'}<=$y) 
+)
        {
        ++$person_count;
        $vision_total=$vision_total+$HoH{$id}->{'vision'};
        }
    }
    return int($person_count);
}

sub percent
{
    ($x,$y) = @_;
    $percent = 0;
    my ($total_person_count,$vision_total,$person_count)=0;
    foreach my $id (sort keys %HoH)
    {
        ++$total_person_count;
    }

    foreach my $id (sort keys %HoH)
    {
        if( ($HoH{$id}->{'vision'}>=$x) & ($HoH{$id}->{'vision'}<=$y) 
+)
        {
        ++$person_count;
        $vision_total=$vision_total+$HoH{$id}->{'vision'};
        }
    }
    return $percent = ($person_count/$total_person_count)*100;
}
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