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Many of the fastest growing Evangelicalchurches in the world do not belong to any "established" denomination, though the tendency is that over time the larger ones form their own organization (typically without calling it a "denomination").
References
Patterson, Eric; Rybarczyk, Edmund J. The Future of Pentecostalism in the United States, Rowman & Littlefield, 2007, ISBN0-7391-2103-0