Year Percent change (Units) 2005 36.959 2006 53.231 2007 30.835 2008 2.668 2009 -2.801 2010 2.430 2011 5.604 2012 6.089 2013 1.879 2014 2.236 2015 1.393 2016 0.458 2017 0.200 2018 0.351 2019 -0.199 2020 0.574 2021 6.042 2022 4.987 2023 4.416 2024 4.000 2025 4.000 2026 3.800 2027 3.800 2028 3.700 2029 3.600