hello. i am still new in using php coding.i hope anybody can explain me detail how to solve my problem.i want to generate a bar graph. the value is automatically update from my total of registered user in a month.after do some research i have found a code how to build a bar graph.here is it

Code:
<?
# ------- The graph values in the form of associative array
$values=array(
"Jan" => 110,
"Feb" => 130,
"Mar" => 215,
"Apr" => 81,
"May" => 310,
"Jun" => 110,
"Jul" => 190,
"Aug" => 175,
"Sep" => 390,
"Oct" => 286,
"Nov" => 150,
"Dec" => 196
);



$img_width=450;
$img_height=300;
$margins=20;



# ---- Find the size of graph by substracting the size of borders
$graph_width=$img_width - $margins * 2;
$graph_height=$img_height - $margins * 2;
$img=imagecreate($img_width,$img_height);



$bar_width=20;
$total_bars=count($values);
$gap= ($graph_width- $total_bars * $bar_width ) / ($total_bars +1);



# ------- Define Colors ----------------
$bar_color=imagecolorallocate($img,0,64,128);
$background_color=imagecolorallocate($img,240,240,255);
$border_color=imagecolorallocate($img,200,200,200);
$line_color=imagecolorallocate($img,220,220,220);

# ------ Create the border around the graph ------


imagefilledrectangle($img,1,1,$img_width-2,$img_height-2,$border_color);
imagefilledrectangle($img,$margins,$margins,$img_width-1-$margins,$img_height-1-$margins,$background_color);



# ------- Max value is required to adjust the scale -------
$max_value=max($values);
$ratio= $graph_height/$max_value;



# -------- Create scale and draw horizontal lines --------
$horizontal_lines=20;
$horizontal_gap=$graph_height/$horizontal_lines;


for($i=1;$i<=$horizontal_lines;$i++){
$y=$img_height - $margins - $horizontal_gap * $i ;
imageline($img,$margins,$y,$img_width-$margins,$y,$line_color);
$v=intval($horizontal_gap * $i /$ratio);
imagestring($img,0,5,$y-5,$v,$bar_color);


}


# ----------- Draw the bars here ------
for($i=0;$i< $total_bars; $i++){
# ------ Extract key and value pair from the current pointer position
list($key,$value)=each($values);
$x1= $margins + $gap + $i * ($gap+$bar_width) ;
$x2= $x1 + $bar_width;
$y1=$margins +$graph_height- intval($value * $ratio) ;
$y2=$img_height-$margins;
imagestring($img,0,$x1+3,$y1-10,$value,$bar_color);
imagestring($img,0,$x1+3,$img_height-15,$key,$bar_color);
imagefilledrectangle($img,$x1,$y1,$x2,$y2,$bar_color);
}
header("Content-type:image/png");
imagepng($img);


?>
i need a help.how i can get the value for x is month and y is total user that registered for each month. here is some detail that i can provide. help me please

HTML Code:
CREATE TABLE `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) NOT NULL DEFAULT '',
`address` varchar(100) NOT NULL DEFAULT '',
`day` int(10) NOT NULL,
`month` varchar(15) NOT NULL,
`years` int(10) NOT NULL,
`number` varchar(15) NOT NULL,
`gender` varchar(100) NOT NULL,
`email` varchar(100) NOT NULL,
`password` varchar(100) NOT NULL DEFAULT '',
`time` time NOT NULL,
`date` date NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=114 DEFAULT CHARSET=latin1
Code:
<?php




$user = $fullname = $address = $day = $month =$years =$number = $gender = $email = $password = $repeatpassword = $time = $date ="";


if(isset($_POST['fullname'])) //check for existance <- ni check isset utk 1 form je dah ckp. isset tu yg biasa guna utk cek variable kosong ke x
{



//form data
$fullname= strip_tags($_POST['fullname']);
$address= strip_tags($_POST['address']);
$day=strip_tags($_POST['day']);
$month=strip_tags($_POST['month']);
$years=strip_tags($_POST['years']);
$number=strip_tags($_POST['number']);
$gender=strip_tags($_POST['gender']);
$email= strip_tags($_POST['email']);
$password= strip_tags($_POST['password']);
$repeatpassword= strip_tags($_POST['repeatpassword']);
$time = date("H:i",time());
$date = date('y/m/d', time()); ///date for registered user

// echo $fullname;


//encrypt password

//$repeatpassword=md5($repeatpassword); ni tak perlu sebab yg kau nak simpan dalam database password je so aku dah 'comment' kan. (boleh padam bila2)

if($password==$repeatpassword)
{

//check char length of username and fullname
if (strlen($email)>25||strlen($fullname)>25){
echo "email or fullname is too long!";
} else {
//check password length
if (strlen($password)>25||strlen($password)<6){
echo "your password must be between 6 to 25 characters";
} else {
//register the user!

//encrypt password
$password=md5($password);

//Open database
$connect = mysql_connect("localhost","root","");
mysql_select_db("phplogin"); //select database

$queryreg = mysql_query("

INSERT INTO users VALUES ('','$fullname','$address','$day','$month','$years','$number','$gender','$email','$password','$time','$date')

");

echo("You have been registered! <a href='index.php'>Return to login page</a>");
}
}
} else {
echo "Your password do not match!";
}

}

?>