Year Percent 1997-01-01 0.0055000000000000000 1998-01-01 0.0018480000000000000 1999-01-01 0.0018390000000000001 2000-01-01 0.0000550000000000000 2001-01-01 0.0030670000000000003 2002-01-01 0.0045170000000000000 2003-01-01 0.0096470000000000000 2004-01-01 0.0112800000000000000 2005-01-01 0.0187040000000000000 2006-01-01 0.0360860000000000000 2007-01-01 0.0369100000000000050 2008-01-01 0.0353700000000000000 2009-01-01 0.0569940000000000000 2010-01-01 0.0891120000000000000 2011-01-01 0.1148700000000000000 2012-01-01 0.1784130000000000200 2013-01-01 0.1654650000000000000 2014-01-01 0.1189200000000000000 2015-01-01 0.1431720000000000000