Cheers for the help dave! here's my entire code:

CustData.txt
---------------------------------------------
1001,Lord,Flintstone,Fred,M,11/01/1980,99
1002,Lady,Flintstone,Wilma,F,11/03/1988,51
1003,Miss,Flintstone,Pebbles,F,01/01/1999,55
---------------------------------------------
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#!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);



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;
}

print("\nDo you want to print to screen of to a file? [s] or [f]: ");
$question=<STDIN>;
while ($question !~ m/[sSfF]/)
{
    print("Please type [s] or [f]\n");
}
if ($question =~ m/[sS]/)
{
    $range1=1;
    $range2=10;
    $range3=1;
    $range4=10;
    $person_count=0;
    print("\n");
    print("Range\t01-10\t11-20\t21-30\t31-40\t41-50\t51-60\t61-70\t71-
+80\t81-90\t91-99\n");
    print("Count");
    for ($counter=0;$counter<10;$counter++)
    {
        $range3=$range3+10;
        $range4=$range4+10;
        print ("\t  ".personCount($range3,$range4));
    }
    print("\n");
    
    print("Percent\t");
    for ($counter=0;$counter<10;$counter++)
    {
        $range1=$range1+10;
        $range2=$range2+10;
        printf("  %.0f\t",(percent($range1,$range2)));
    }
    print("\n\n");
}
elsif ($question =~ m/[fF]/)
{
    FILENAME:
    {
        print("\nFilename: ");
        chomp($filename=<STDIN>);
        while ($filename !~ m/^[a-zA-Z]{1}\w{2,7}$/ || $filename =~ m/
+\./)
        {
            print("\nInvalid filename.\n Please try again.\n");
            redo FILENAME;
        }
        if (-e $path)
        {
            print("File exists. Overwrite? [y] or [n]: ");
            $exists=<STDIN>;
            while ($exists !~ m/[yYnN]/)
            {
                print("Please type [y] or [n]\n");
            }
            if ($exists =~ m/[nN]/)
            {
                redo FILENAME;
            }
            else
            {
                print("\n[Saved as ".$filename.".txt]\n\n");
            }
        }
        else
        {
            print("\n[Saved as ".$filename.".txt]\n\n");
        }
    }
    
    my $path=($filename.".txt");
    open (DATA, ">$path") || die "\nCouldn't open $path for writing: $
+!\n";
    
          $range1=1;
        $range2=10;
        $range3=1;
        $range4=10;
        $person_count=0;
        print DATA ("Range\t01-10\t11-20\t21-30\t31-40\t41-50\t51-60\t
+61-70\t71-80\t81-90\t91-99    \n");
        print DATA ("Count");
        for ($counter=0;$counter<10;$counter++)
        {
            $range3=$range3+10;
            $range4=$range4+10;
            print DATA ("\t  ".personCount($range3,$range4));
        }
        print DATA ("\n");
        
    
        print DATA ("Percent\t");
        for ($counter=0;$counter<10;$counter++)
        {
            $range1=$range1+10;
            $range2=$range2+10;
            printf DATA ("  %.0f\t",(percent($range1,$range2)));
        }
        print DATA ("\n");
    
close(DATA);
}
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