My code below creates a line chart but I only have two categories on the x axis. How can I reduce the horiz size so it doesn't look so silly?

<?php

LineChart::create(array(
    "dataStore"=>$this->dataStore("results"),

    "columns"=>array(
        "type",
        "wages"=>array(
            "label"=>"Wages",
            "type"=>"number",
            "prefix"=>"$"
        ),
        "supplies"=>array(
            "label"=>"Supplies",
            "type"=>"number",
            "prefix"=>"$"
        ),
        "computer_rental"=>array(
            "label"=>"Computer_rental",
            "type"=>"number",
            "prefix"=>"$",
            "axis"=>"y2"
        ),
        "contract_research"=>array(
            "label"=>"Contracts",
            "type"=>"number",
            "prefix"=>"$",
            "axis"=>"y2"
        ),
    ),
    "yAxis"=>array(
        "prefix"=>"$"
    ),
    "dualAxis"=>true
));
?>