Year Percent change (Units) 1996 11.952 1997 12.246 1998 14.432 1999 -2.515 2000 23.210 2001 3.118 2002 4.824 2003 14.080 2004 4.775 2005 9.970 2006 15.373 2007 10.058 2008 7.051 2009 -5.935 2010 12.458 2011 7.690 2012 3.971 2013 5.068 2014 5.514 2015 6.589 2016 9.005 2017 9.046 2018 6.759 2019 5.337 2020 -1.088 2021 12.335 2022 6.743 2023 -1.941 2024 6.465 2025 3.035 2026 4.000 2027 4.000 2028 4.000 2029 4.000