Complex sentence: As many as 40 contestants selected via local pageants across many provinces of Canada competed in the annual Niagara Falls competition, however, throughout the 1970s, there were generally between twelve and twenty contestants.
Split into simpler sentences: As many as 40 contestants selected via local pageants across many provinces of Canada competed in the annual Niagara Falls competition. Throughout the 1970s, there were generally between twelve and twenty contestants.