Year Percent change (Units) 2000 29.864 2001 23.729 2002 19.701 2003 7.502 2004 3.099 2005 3.446 2006 2.116 2007 3.365 2008 9.000 2009 3.551 2010 0.381 2011 3.451 2012 4.141 2013 2.207 2014 -0.714 2015 1.549 2016 -0.258 2017 2.373 2018 2.604 2019 0.366 2020 -0.238 2021 2.399 2022 13.050 2023 8.565 2024 4.164 2025 2.721 2026 2.051 2027 1.976 2028 1.942 2029 1.934