Year Percent change (Units) 1996 29.291 1997 10.673 1998 7.862 1999 6.618 2000 6.938 2001 18.869 2002 12.883 2003 14.033 2004 15.001 2005 17.856 2006 8.218 2007 5.401 2008 11.581 2009 12.536 2010 13.742 2011 10.825 2012 12.225 2013 8.495 2014 8.048 2015 9.010 2016 15.696 2017 16.502 2018 12.094 2019 11.397 2020 13.247 2021 16.953 2022 18.847 2023 24.660 2024 26.311 2025 22.972 2026 16.017 2027 15.382 2028 14.000 2029 14.000