Year Number 2008-01-01 1672 2009-01-01 1880 2010-01-01 2128 2011-01-01 2367 2012-01-01 2493 2013-01-01 3120 2014-01-01 3407 2015-01-01 3581 2016-01-01 3824 2017-01-01 3961