Year Percent change (Units) 1992 -1.540 1993 -7.868 1994 4.107 1995 -6.164 1996 12.253 1997 19.731 1998 -13.190 1999 -5.567 2000 -9.177 2001 -8.245 2002 -2.277 2003 4.436 2004 6.621 2005 1.910 2006 30.736 2007 2.506 2008 -7.149 2009 18.531 2010 25.592 2011 6.539 2012 19.140 2013 6.276 2014 -39.182 2015 -6.393 2016 -15.012 2017 29.471 2018 7.163 2019 3.189 2020 -6.426 2021 5.513 2022 8.116 2023 2.927 2024 -1.848 2025 6.283 2026 4.807 2027 3.650 2028 3.622 2029 3.818