Year Percent change (Units) 1992 3.371 1993 4.438 1994 6.505 1995 4.886 1996 3.513 1997 2.520 1998 2.205 1999 -0.401 2000 1.184 2001 1.891 2002 1.404 2003 1.590 2004 2.439 2005 3.281 2006 3.514 2007 5.896 2008 8.730 2009 5.551 2010 2.485 2011 5.242 2012 4.221 2013 1.063 2014 1.342 2015 -0.522 2016 2.403 2017 0.577 2018 0.139 2019 3.318 2020 1.779 2021 1.181 2022 5.172 2023 1.800 2024 1.811 2025 1.903 2026 1.951 2027 2.000 2028 2.009 2029 1.995