Complex sentence: Football in Niger is almost entirely amateur, with some of the ten teams in the Niger Premier League (begun in 1966) being semi-professional, and the Niger Cup (begun in 1974) open to amateur leagues throughout the nation.
Split into simpler sentences: Football in Niger is almost entirely amateur, with some of the ten teams in the Niger Premier League (begun in 1966) being semi-professional. The Niger Cup (begun in 1974) is open to amateur leagues throughout the nation.