Year Percent change (Units) 1993 534.180 1994 1568.333 1995 304.597 1996 53.961 1997 70.857 1998 28.981 1999 29.103 2000 25.006 2001 27.251 2002 27.291 2003 12.494 2004 7.325 2005 10.703 2006 13.109 2007 11.154 2008 13.128 2009 12.298 2010 12.304 2011 12.447 2012 11.900 2013 11.700 2014 9.079 2015 8.464 2016 8.824 2017 13.876 2018 17.524 2019 14.526 2020 12.868 2021 10.849 2022 11.447 2023 9.951 2024 11.579 2025 9.691 2026 7.671 2027 5.923 2028 5.039 2029 5.004