Year Percent change (Units) 1996 8.736 1997 10.085 1998 6.832 1999 2.326 2000 3.977 2001 4.098 2002 0.656 2003 1.043 2004 2.710 2005 2.261 2006 1.720 2007 5.435 2008 3.666 2009 0.994 2010 2.298 2011 2.353 2012 2.403 2013 1.429 2014 0.101 2015 0.000 2016 2.010 2017 2.365 2018 2.021 2019 3.208 2020 2.285 2021 6.613 2022 15.759 2023 6.879 2024 2.150 2025 2.000 2026 2.000 2027 2.000 2028 2.000 2029 2.000