PHP クラスプロパティ

<?php
class User
{
    public $name;
    public $score;
    public static $count = 0;

    public function __construct($name, $score)
    {
        $this->name = $name;
        $this->score = $score;
        User::$count++;
    }
}

// $count = 0;
$user1 = new User("Taro", 70);
// $count++;
$user2 = new User("Jiro", 90);
// $count++;

// echo $count . PHP_EOL;
echo User::$count . PHP_EOL;