Year Percent change (Units) 1980 12.663 1981 8.445 1982 4.482 1983 -3.217 1984 1.248 1985 0.480 1986 1.424 1987 0.815 1988 0.682 1989 -2.749 1990 6.215 1991 1.020 1992 2.446 1993 4.583 1994 3.496 1995 3.637 1996 1.872 1997 4.552 1998 2.823 1999 4.205 2000 0.888 2001 3.450 2002 2.033 2003 2.474 2004 1.944 2005 3.403 2006 0.772 2007 3.063 2008 4.956 2009 -0.453 2010 4.000 2011 1.506 2012 2.799 2013 1.054 2014 0.425 2015 1.301 2016 1.066 2017 1.468 2018 1.389 2019 1.370 2020 0.189 2021 2.593 2022 7.721 2023 4.192 2024 2.182 2025 2.059 2026 1.998 2027 1.998 2028 1.998 2029 2.000