Complex sentence: Despite this decline, the 2010 figure actually had moved Canton up from 9th to 8th place among Ohio cities, as nearby Youngstown in neighboring Mahoning County, once considerably more populous than Canton, had suffered a larger decline.
Split into simpler sentences: Despite this decline, the 2010 figure actually moved Canton from ninth to eighth place among Ohio cities. Nearby Youngstown in adjoining Mahoning County, once considerably more populous than Canton, suffered a larger decline.