What is the highest level a Pokémon in a swarm could possibly be at?

Question

In Gen V, swarms of Pokémon have a wide variety of levels. What is the highest level a Pokémon in a swarm can be found at?

Answer 1

All have the level range of 15-55.

So thats basically it.
Source: http://bulbapedia.bulbagarden.net/wiki/Pokémon_outbreak

Hope this helped!