GD::Graph line problem

[ultibuzz]

Hello,
i have a graph with dates as x ticks and i only want to schow 20 ticks on the axe.
i tryed now label skip and offset but didn't work,with max ticks i can not work because its not numerical.

DATA

___DATA.txt___
01.10,75034
02.10,75722
03.10,75717
04.10,76427
05.10,76669
06.10,77256
07.10,77155
08.10,77135
09.10,77443
10.10,78347
11.10,78776
12.10,79252
13.10,79980
14.10,79945
15.10,79913
16.10,80451
17.10,80869
18.10,81144
19.10,81129
20.10,81625
21.10,81602
22.10,81599
23.10,82508
24.10,83697
25.10,84712
26.10,86267
27.10,87164
28.10,86921
29.10,86915
30.10,87913
31.10,88536
01.11,88598
02.11,89824
03.11,90815
04.11,90653
05.11,90620
06.11,91661
07.11,92231
08.11,93556
09.11,94816
10.11,96083
11.11,95969
12.11,95967
13.11,97054
14.11,97660
15.11,98428
16.11,98386
17.11,98308
18.11,98093
19.11,98088
20.11,98783
21.11,99311
22.11,100030
23.11,100630
24.11,100089
25.11,99854
26.11,99849
27.11,101942
28.11,102804
29.11,103813
30.11,105188
01.12,106007
02.12,105982
03.12,105982
04.12,106672
05.12,107552
06.12,108083
07.12,108101
08.12,107792
09.12,107726
10.12,107699
11.12,107708
12.12,107693
13.12,107551
14.12,107275
15.12,107247
16.12,107246
17.12,107240

and here is the code

#!"C:\perl\bin\perl.exe"

use DBI;
use POSIX qw(strftime);
use GD::Graph::lines;
use GD::Graph::colour;
use GD::Text;
use GD::Graph::Data;
use warnings;
use strict;

my $data = GD::Graph::Data->new();

$data->read(file => "data.txt", delimiter => ',');

my $graph = new GD::Graph::lines( 800, 600 );

$graph->set_title_font('arial.ttf', 20);
$graph->set_values_font('arial.ttf', 5);
$graph->set_x_label_font('arial.ttf', 12);
$graph->set_y_label_font('arial.ttf', 12);
$graph->set_x_axis_font('arial.ttf', 8);
$graph->set_y_axis_font('arial.ttf', 12);

$graph->set( 
        y_label           => 'Active',
        title             => '===> flow <===',
        y_max_value       => 120000,
        y_min_value       => 70000,
        y_tick_number     => 10,
        y_lable_skip      => 2,
        x_tick_offset      => 15,
        transparent          => 1,
        values_vertical      => 1,
        show_values          => 1,
        line_width        => 2,
        dclrs              => [ qw(red)]
);

my $gd = $graph->plot( $data );

open(IMG, ">chart.gif") or die $!;
binmode IMG;
print IMG $gd->gif;
close IMG;

kd ultibuzz