Magento : get present in product price

<?php
       $price_f1 = ltrim(  Mage::helper('core')->currency($_product->getPrice(),true,false),'$');
       $price_f2 = trim(    Mage::helper('core')->currency($_product->getFinalPrice(),true,false) ,'$');
       $discount_total_p = number_format($price_f1-$price_f2,2);
       $percente_zz= number_format( $discount_total_p/$price_f1*100 ,0);
echo   $percente_xyz = $percente_zz.'%';
?>