Complex sentence: The overall total production in 1985 was 6.3 million metric tons (mmt); by the end of 2008 it had reached 56 mmt and by 2020, SABIC intends to produce over 135 mmt per year.
Split into simpler sentences: The overall total production in 1985 was 6.3 million metric tons; by the end of 2008 it had reached 56 million metric tons. By 2020, SABIC intends to produce over 135 million metric tons per year.