Year Percent 1998-01-01 0.009670999999999999 1999-01-01 0.011120000000000000 2000-01-01 0.009220000000000000 2001-01-01 0.008056000000000000 2002-01-01 0.008912999999999999 2003-01-01 0.009047000000000000 2004-01-01 0.018155000000000000 2005-01-01 0.006412999999999999 2006-01-01 0.006923000000000000 2007-01-01 0.010345000000000000 2008-01-01 0.010976000000000000 2009-01-01 0.022252000000000000 2010-01-01 0.014825000000000000 2011-01-01 0.011352000000000000 2012-01-01 0.010430000000000000 2013-01-01 0.012972999999999998 2014-01-01 0.012714000000000000 2015-01-01 0.018550999999999998