Complex sentence: The following year, "Anthology" was certified six-time platinum (Spanish) by the RIAA, and was the vast majority of EMI Latin's total album sales in 1998 and 1999, selling 343,000 units.
Split into simpler sentences: The following year, "Anthology" was released and was certified six-time platinum (Spanish) by the RIAA. It was the vast majority of EMI Latin's total album sales in 1998 and 1999, selling 343,000 units.