Year Percent change (Units) 1995 2.600 1996 10.500 1997 10.527 1998 3.104 1999 2.953 2000 1.757 2001 4.885 2002 5.358 2003 11.779 2004 5.796 2005 9.588 2006 9.420 2007 12.579 2008 2.419 2009 -3.651 2010 6.942 2011 7.949 2012 6.579 2013 5.134 2014 4.091 2015 3.351 2016 3.450 2017 5.161 2018 6.062 2019 5.380 2020 -6.291 2021 10.644 2022 10.960 2023 7.474 2024 5.740 2025 5.232 2026 4.697 2027 4.852 2028 5.000 2029 5.000