/**
* Create a new iterator for the number of years in a range.
*
* @param DateTime $start The start date of the range
* @param DateTime $end The end date of the range
*/
public function __construct(DateTime $start, DateTime $end)
{
$this->start = $start->getYear()->getStart()->timestamp();
$this->end = $end->getYear()->getStart()->timestamp();
$this->rewind();
}