Complex sentence: Thanks to the stability of the Mexican economy and the growth in foreign investment, the Mexican peso is now among the 15 more traded currency units in years; since the late 1990s the peso has traded at about 9 to 15 pesos per U.S. dollar.
Split into simpler sentences: Thanks to the stability of the Mexican economy and the growth in foreign investment, the Mexican peso is now among the 15 more traded currency units in recent years. Since the late 1990s the peso has traded at about 9 to 15 pesos per U.S. dollar.