Adjust Y-axis scale 

@@ -27,6 +27,8 @@
     bgclr              => 'white',
     box_axis           => 0,
     dclrs              => ['#ff782a', '#6daa3a', '#4d7296'],
+    y_max_value        => 60,
+    y_tick_number      => 3,
 ) or die $graph->error;
 
 $graph->set_legend(@products);