Year Percent change (Units) 2000 4.993 2001 16.351 2002 19.334 2003 35.760 2004 31.677 2005 31.616 2006 64.826 2007 4.671 2008 6.752 2009 -4.413 2010 3.312 2011 6.020 2012 3.614 2013 3.132 2014 1.587 2015 2.310 2016 -0.670 2017 0.771 2018 -0.096 2019 0.096 2020 3.155 2021 5.283 2022 4.313 2023 3.966 2024 4.000 2025 4.000 2026 3.800 2027 3.700 2028 3.600 2029 3.500