Year Percent change (Units) 1999 1.982 2000 5.300 2001 12.149 2002 14.160 2003 10.330 2004 3.555 2005 6.945 2006 9.514 2007 11.391 2008 17.490 2009 7.427 2010 7.291 2011 8.487 2012 6.832 2013 7.578 2014 9.858 2015 7.742 2016 8.844 2017 12.435 2018 23.547 2019 26.969 2020 16.953 2021 7.816 2022 7.593 2023 10.094 2024 6.344 2025 5.111 2026 5.070 2027 4.949 2028 4.876 2029 4.831