Display total in sales by client report

<html>
	<head>
		<title><?php echo lang('sales_by_client'); ?></title>
		<link rel="stylesheet" href="<?php echo base_url(); ?>assets/default/css/reports.css" type="text/css">
	</head>
	<body>

		<h3 class="report_title"><?php echo lang('sales_by_client'); ?></h3>

		<table>
			<tr>
				<th><?php echo lang('client'); ?></th>
				<th class="amount"><?php echo lang('invoice_count'); ?></th>
				<th class="amount"><?php echo lang('sales'); ?></th>
				<th class="amount"><?php echo lang('sales_with_tax'); ?></th>
			</tr>
			<?php
				$report_inv_count= 0;
				$report_total= 0;
				$report_total_tax= 0;
			foreach ($results as $result) {
			?>
			<tr>
				<td><?php echo $result->client_name; ?></td>
				<td class="amount"><?php echo $result->invoice_count; $report_inv_count+=$result->invoice_count; ?></td>
				<td class="amount"><?php echo format_currency($result->sales); $report_total+=$result->sales; ?></td>
				<td class="amount"><?php echo format_currency($result->sales_with_tax); $report_total_tax+=$result->sales_with_tax; ?></td>
			</tr>
			<?php } ?>
			<tr>
				<td><?php echo '<b>Total</b>'; ?></td>
				<td class="amount"><?php echo '<b>'.$report_inv_count.'</b>'; ?></td>
				<td class="amount"><?php echo '<b>'.format_currency($report_total).'</b>'; ?></td>
				<td class="amount"><?php echo '<b>'.format_currency($report_total_tax).'</b>'; ?></td>
			</tr>
		</table>
	</body>
</html>