Year Percent change (Units) 1982 0.000 1983 1.166 1984 3.098 1985 2.131 1986 1.781 1987 1.247 1988 1.193 1989 1.304 1990 2.139 1991 1.600 1992 1.280 1993 4.252 1994 2.463 1995 5.967 1996 1.996 1997 1.712 1998 -0.441 1999 -0.416 2000 1.558 2001 0.596 2002 -2.315 2003 0.300 2004 0.814 2005 1.244 2006 0.160 2007 0.968 2008 2.085 2009 1.036 2010 0.357 2011 0.138 2012 0.112 2013 0.389 2014 -0.207 2015 -0.488 2016 -0.279 2017 -1.261 2018 1.025 2019 -0.391 2020 1.940 2021 1.733 2022 3.683 2023 0.370 2024 1.300 2025 1.000 2026 1.000 2027 1.000 2028 1.000 2029 1.000