Year Percent 1998-01-01 14.59850 1999-01-01 19.87710 2000-01-01 29.81120 2001-01-01 26.63240 2002-01-01 27.55730 2003-01-01 34.33910 2004-01-01 43.13250 2005-01-01 35.01830 2006-01-01 27.98280 2007-01-01 28.27710 2008-01-01 18.04920 2009-01-01 11.40010 2010-01-01 12.35530 2011-01-01 8.81366 2012-01-01 8.47478