Year Percent change (Units) 1993 12.882 1994 20.918 1995 2.325 1996 9.136 1997 7.900 1998 1.966 1999 0.187 2000 -12.355 2001 8.755 2002 3.005 2003 -2.656 2004 1.452 2005 2.574 2006 -0.969 2007 1.427 2008 -19.436 2009 12.179 2010 10.853 2011 25.710 2012 1.886 2013 -10.456 2014 30.934 2015 -20.621 2016 7.391 2017 -10.015 2018 13.032 2019 3.836