PHP从循环中保存增量变量

How can I save last increment inside variable?

and it is that possible?

abstract class myClass()
{
   private $increment = 0;

   public function run()
   {
     foreach ( .... ){
       $this->increment++;

Now every time it is call the loop, the increment variable start from zero, that because is a new instance of class.

There is a way for continue from last increment variable?

Any suggestion?

EDIT: class is abstract

thanks