Complex sentence: In five years, global sales of highway legal light-duty plug-in electric vehicles increased more than ten-fold, totaling more than 565,000 units in 2015-itself an 80% increase from 2014, driven mainly by China and Europe.
Split into simpler sentences: In five years, global sales of highway legal light-duty plug-in electric vehicles have increased more than ten-fold, totaling more than 565,00 units in 2015. Plug-in sales in 2015 increased about 80% from 2014, driven mainly by China and Europe.