The NY Times is sticking with "dozens" right now. But The Guardian says:
At least 550 pilgrims have died during the hajj, underscoring the gruelling nature of the pilgrimage which again unfolded in scorching temperatures this year.
...
Each year tens of thousands of pilgrims attempt to perform the hajj without securing official hajj visas in order to save money, a more dangerous undertaking because these off-the-books pilgrims cannot access air-conditioned facilities provided by Saudi authorities along the hajj route.