The research team compared the Milky Way to similar galaxies in terms of luminosity--a measure of how much light is emitted--and distance to other bright galaxies. They found galaxies that have two satellites that are as bright and close by as the Milky Way's two closest satellites, the Large and Small Magellanic Clouds, are rare.
http://www.usnews.com/science/articles/2011/05/24/just-four-percent-of-galaxies-have-neighbors-like-the-milky-way