Year Percent 1997-01-01 0.657263000000000000 1998-01-01 0.245150000000000000 1999-01-01 0.031692000000000005 2000-01-01 0.015116000000000000 2001-01-01 0.027864999999999997 2002-01-01 0.029829000000000000 2003-01-01 0.166305000000000000 2004-01-01 0.018306000000000000 2005-01-01 0.056541999999999995 2006-01-01 0.038970000000000000 2007-01-01 0.050013999999999996 2008-01-01 0.042934000000000000 2009-01-01 0.061127999999999995 2010-01-01 0.045556000000000000 2011-01-01 0.037235000000000004 2012-01-01 0.020093000000000000 2013-01-01 0.011844000000000000