Year Percent change (Units) 1993 -10.000 1994 -17.300 1995 -7.200 1996 -6.700 1997 -11.300 1998 6.700 1999 16.499 2000 18.587 2001 20.391 2002 15.768 2003 17.095 2004 14.692 2005 13.040 2006 10.967 2007 11.057 2008 14.747 2009 6.133 2010 16.026 2011 12.660 2012 7.209 2013 -1.754 2014 3.605 2015 2.159 2016 -0.466 2017 2.141 2018 1.740 2019 -3.666 2020 -2.116 2021 -0.338 2022 5.315 2023 1.954 2024 2.293 2025 2.262 2026 2.272 2027 2.257 2028 2.246 2029 2.246