Year Percent change (Units) 1990 5.400 1991 0.763 1992 -7.846 1993 6.475 1994 -5.968 1995 -9.890 1996 -5.274 1997 -0.428 1998 4.293 1999 -5.843 2000 -5.386 2001 8.252 2002 5.219 2003 10.407 2004 -4.052 2005 11.268 2006 4.828 2007 -2.051 2008 4.807 2009 6.565 2010 1.368 2011 -5.103 2012 4.590 2013 3.642 2014 10.084 2015 -2.853 2016 -23.563 2017 52.549 2018 9.327 2019 12.350 2020 -29.504 2021 37.324 2022 4.438 2023 1.155 2024 -1.166 2025 1.266 2026 3.777 2027 6.208 2028 3.225 2029 1.079