Year Percent change (Units) 1996 1.960 1997 10.729 1998 12.015 1999 2.820 2000 16.509 2001 14.927 2002 8.214 2003 12.716 2004 40.700 2005 22.963 2006 14.365 2007 11.620 2008 4.177 2009 -10.550 2010 15.927 2011 10.150 2012 4.182 2013 0.693 2014 9.308 2015 5.200 2016 4.398 2017 7.162 2018 3.539 2019 1.334 2020 -6.257 2021 6.878 2022 5.899 2023 2.175 2024 0.444 2025 3.999 2026 4.150 2027 4.550 2028 4.633 2029 4.800