In a certain factory, the union membership was higher in 2010 than in 2008. For the period from 2007 to 2011, the percentage of factory workers that were members of the union remained constant. The statements above, if true, most strongly support which conclusion? ['Throughout this entire manufacturing sector, factory worker unions saw growth from 2008 to 2010', 'The union membership in 2009 was higher than it was in 2008', 'The factory had more employees in 2010 than in 2008', 'In 2010, there were fewer non-union employees in this factory than there were in 2008']