Year Number 2007-01-01 294.004779104565 2008-01-01 309.535835483072 2009-01-01 460.954701010935 2010-01-01 468.978539879216 2011-01-01 500.604885226992 2012-01-01 639.218811440535 2013-01-01 645.333226513873 2014-01-01 647.924214881397 2015-01-01 661.890438185467