Year Number 2008-01-01 4763831 2009-01-01 4891639 2010-01-01 5594268 2011-01-01 7408211 2012-01-01 9105588 2013-01-01 10559521 2014-01-01 10320924 2015-01-01 12903037 2016-01-01 13740247