Year Percent change (Units) 1980 9.000 1981 8.800 1982 -2.100 1983 7.200 1984 7.200 1985 27.900 1986 21.500 1987 9.300 1988 12.300 1989 20.200 1990 59.800 1991 10.032 1992 14.220 1993 11.644 1994 11.610 1995 8.607 1996 10.849 1997 7.149 1998 7.466 1999 4.915 2000 5.072 2001 8.917 2002 6.310 2003 5.877 2004 9.215 2005 8.563 2006 5.789 2007 8.764 2008 9.401 2009 -0.293 2010 5.402 2011 6.206 2012 3.431 2013 4.396 2014 2.949 2015 3.057 2016 4.241 2017 5.677 2018 2.315 2019 3.407 2020 4.819 2021 3.061 2022 9.241 2023 4.178 2024 4.000 2025 4.033 2026 3.975 2027 4.033 2028 4.033 2029 4.033