Year Percent change (Units) 1993 2.800 1994 5.300 1995 4.100 1996 3.203 1997 5.050 1998 3.280 1999 5.332 2000 3.673 2001 3.217 2002 3.506 2003 2.960 2004 4.359 2005 3.798 2006 5.746 2007 6.980 2008 3.510 2009 -7.549 2010 1.344 2011 0.861 2012 -2.640 2013 -1.029 2014 2.768 2015 2.210 2016 3.192 2017 4.816 2018 4.455 2019 3.523 2020 -4.241 2021 8.229 2022 2.461 2023 1.587 2024 2.010 2025 2.500 2026 2.700 2027 2.700 2028 2.700 2029 2.700