I got 'stuck' on this issue when I was awakening...I kept thinking, JWs are the only ones trying to reach so many people throughout the earth, really they're only ones preaching the good news worldwide. Then JWfacts.com pointed out the success of different ministries such as the JesusFilm project.
The Jesus film project is a non-denominational 2 hour movie which is a simple film version of Jesus life and ministry based on Luke's gospel. It has been used by various missionary groups for 35 years, and has been translated to 1300 languages, they take it to all sorts of far flung places, tribes etc where internet may not even be heard of. Estimated billions of people have seen the film and 200million have decided to become Christians as a result of seeing the film.
Although I don't back any one denomination, I did feel misled by the witnesses into believing that they were the only ones really accomplishing any significant preaching work, as of course they neglect to tell anyone about other preaching missions like this one.
http://www.jesusfilm.org/film-and-media/statistics/statistics