Complex sentence: Protestants in Vietnam are a small religious minority in Vietnam, constituting only 1.2% of the population, or one million persons, and is the fastest growing religion in Vietnam, growing at a rate of 600% in the last decade.
Split into simpler sentences: Protestants in Vietnam are a small religious minority in Vietnam, constituting only 1.2% of the population, or one million persons. However, it is the country's fastest-growing religion, growing at a rate of 600% in the last decade.