Year Percent change (Units) 1992 3.869 1993 5.408 1994 5.737 1995 4.706 1996 2.631 1997 2.427 1998 2.018 1999 -0.577 2000 2.368 2001 1.424 2002 1.384 2003 1.793 2004 3.073 2005 3.483 2006 3.544 2007 8.168 2008 9.249 2009 2.166 2010 2.798 2011 7.620 2012 1.063 2013 1.063 2014 3.431 2015 -1.610 2016 2.407 2017 -0.843 2018 1.972 2019 3.265 2020 0.302 2021 2.549 2022 3.583 2023 3.300 2024 1.844 2025 1.972 2026 2.060 2027 2.154 2028 2.206 2029 2.235