Year Number 2007-01-01 0 2008-01-01 0 2009-01-01 100000 2010-01-01 200000 2011-01-01 800000 2012-01-01 3300000 2013-01-01 9000000 2014-01-01 15400000 2015-01-01 20100000 2016-01-01 25600