Year Percent change (Units) 1993 17.688 1994 -16.795 1995 20.287 1996 21.600 1997 15.603 1998 0.633 1999 7.678 2000 31.462 2001 17.323 2002 0.529 2003 5.475 2004 30.926 2005 23.544 2006 15.300 2007 25.141 2008 11.573 2009 -14.817 2010 -5.604 2011 9.957 2012 24.259 2013 8.673 2014 -8.752 2015 -5.083 2016 -16.875 2017 8.578 2018 7.011 2019 18.209 2020 -23.862 2021 -8.591 2022 14.568 2023 25.196 2024 6.836 2025 3.713 2026 3.395 2027 3.478 2028 3.426 2029 3.374