public function getConversionRate($idSite, $period, $date, $segment = false, $idGoal = false)
{
$table = $this->get($idSite, $period, $date, $segment, $idGoal, 'conversion_rate');
$table->setMetadata(DataTable::EXTRA_PROCESSED_METRICS_METADATA_NAME, array(new ConversionRate()));
return $table;
}