Year Percent change (Units) 1996 0.000 1997 117.210 1998 -12.348 1999 25.186 2000 28.880 2001 25.949 2002 9.871 2003 1.484 2004 26.485 2005 14.970 2006 15.656 2007 4.013 2008 2.394 2009 0.763 2010 28.783 2011 22.597 2012 11.253 2013 28.166 2014 17.488 2015 18.426 2016 15.666 2017 8.507 2018 13.869 2019 15.013 2020 26.904 2021 -1.189 2022 8.394 2023 4.615 2024 4.785 2025 6.166 2026 6.455 2027 6.691 2028 6.731 2029 6.814