Year Percent change (Units) 1993 22.687 1994 19.288 1995 8.955 1996 9.132 1997 8.787 1998 6.538 1999 7.942 2000 8.930 2001 7.046 2002 7.257 2003 4.613 2004 3.195 2005 2.267 2006 2.786 2007 5.679 2008 2.074 2009 1.770 2010 1.857 2011 2.002 2012 2.676 2013 0.674 2014 0.140 2015 -0.449 2016 0.511 2017 1.745 2018 1.421 2019 1.827 2020 -1.082 2021 4.884 2022 10.256 2023 4.166 2024 2.208 2025 1.976 2026 1.996 2027 2.021 2028 1.996 2029 2.012