Year Percent change (Units) 1980 2.800 1981 -3.514 1982 -11.915 1983 1.510 1984 -19.118 1985 -23.877 1986 48.191 1987 34.989 1988 8.215 1989 2.769 1990 2.035 1991 9.743 1992 9.690 1993 5.224 1994 8.637 1995 5.053 1996 -6.207 1997 15.948 1998 12.751 1999 2.705 2000 23.913 2001 7.560 2002 56.038 2003 8.782 2004 -12.105 2005 -16.599 2006 6.180 2007 12.144 2008 -11.574 2009 -6.421 2010 6.588 2011 -24.030 2012 10.970 2013 2.003 2014 10.806 2015 -0.987 2016 3.827 2017 3.965 2018 -2.808 2019 16.283 2020 -2.401 2021 8.831 2022 -0.427 2023 10.035 2024 1.198 2025 3.634 2026 1.736 2027 1.804 2028 0.905 2029 3.772