Year Percent change (Units) 2004 2.371 2005 6.181 2006 2.575 2007 4.327 2008 16.614 2009 -5.825 2010 5.237 2011 6.324 2012 2.906 2013 0.768 2014 1.289 2015 -3.843 2016 -0.779 2017 1.036 2018 0.676 2019 -1.658 2020 1.541 2021 2.221 2022 5.746 2023 6.000 2024 2.600 2025 2.000 2026 2.000 2027 2.000 2028 2.000 2029 2.000