Year Percent change (Units) 2001 -21.171 2002 -4.379 2003 -13.437 2004 10.554 2005 -22.301 2006 -7.192 2007 -14.749 2008 -10.475 2009 2.830 2010 -5.348 2011 1.067 2012 10.851 2013 6.606 2014 26.444 2015 15.534 2016 6.590 2017 -7.566 2018 -13.530 2019 8.622 2020 18.248 2021 -45.062 2022 -8.197 2023 1.222 2024 15.504 2025 10.207 2026 4.699 2027 1.880 2028 1.383 2029 1.184