Year Percent change (Units) 1980 12.437 1981 1.937 1982 7.774 1983 3.569 1984 -0.334 1985 18.403 1986 5.550 1987 -9.146 1988 2.206 1989 9.633 1990 5.206 1991 20.869 1992 21.019 1993 9.990 1994 1.166 1995 13.354 1996 0.919 1997 -6.420 1998 3.600 1999 7.941 2000 0.662 2001 -8.238 2002 1.654 2003 17.762 2004 3.221 2005 11.656 2006 13.558 2007 17.245 2008 44.371 2009 8.479 2010 8.134 2011 33.232 2012 24.132 2013 8.071 2014 7.404 2015 9.569 2016 6.628 2017 10.687 2018 13.833 2019 15.810 2020 20.354 2021 26.794 2022 33.938 2023 30.219 2024 25.572 2025 18.187 2026 14.281 2027 14.281 2028 14.281 2029 14.281