Year Percent change (Units) 1980 9.689 1981 13.227 1982 6.710 1983 12.538 1984 7.540 1985 9.464 1986 4.380 1987 2.398 1988 1.543 1989 5.608 1990 7.543 1991 8.177 1992 3.895 1993 5.949 1994 5.692 1995 4.148 1996 3.913 1997 1.513 1998 2.219 1999 0.907 2000 1.670 2001 1.706 2002 1.429 2003 1.776 2004 0.542 2005 2.095 2006 3.283 2007 1.986 2008 4.229 2009 -1.614 2010 2.220 2011 0.869 2012 2.583 2013 0.420 2014 1.672 2015 0.617 2016 1.736 2017 1.606 2018 0.198 2019 1.085 2020 -0.293 2021 3.229 2022 8.341 2023 3.412 2024 2.544 2025 2.211 2026 2.260 2027 2.171 2028 2.091 2029 1.997