KpiManager::getAverageAnswerTime

public function getAverageAnswerTime()
{
	$result = 0;
	$messages = $this->getSessionMessages();

	foreach ($messages as $message)
	{
		$result += $this->getMessageAnswerTime($message);
	}

	return count($messages) > 0 ? intval($result/count($messages)) : 0;
}