Year Percent change (Units) 1980 3.099 1981 -1.234 1982 0.414 1983 1.169 1984 3.226 1985 2.798 1986 2.860 1987 3.192 1988 4.194 1989 3.389 1990 2.053 1991 1.435 1992 0.834 1993 -0.853 1994 2.151 1995 2.887 1996 1.197 1997 1.830 1998 1.811 1999 1.626 2000 3.787 2001 1.951 2002 0.254 2003 0.139 2004 1.424 2005 0.818 2006 1.791 2007 1.487 2008 -0.962 2009 -5.281 2010 1.713 2011 0.707 2012 -2.981 2013 -1.841 2014 -0.005 2015 0.778 2016 1.293 2017 1.668 2018 0.926 2019 0.483 2020 -8.974 2021 8.310 2022 3.986 2023 0.921 2024 0.709 2025 0.714 2026 0.170 2027 0.320 2028 0.752 2029 0.834