Year Percent change (Units) 1980 9.190 1981 -4.400 1982 0.596 1983 -3.400 1984 5.307 1985 7.901 1986 7.544 1987 3.601 1988 0.264 1989 3.200 1990 -4.168 1991 1.031 1992 -0.467 1993 4.665 1994 5.334 1995 4.417 1996 2.209 1997 3.395 1998 0.338 1999 0.468 2000 4.388 2001 1.390 2002 3.053 2003 1.141 2004 5.760 2005 3.202 2006 3.962 2007 6.070 2008 5.094 2009 -0.126 2010 7.528 2011 3.974 2012 1.921 2013 3.005 2014 0.504 2015 -3.546 2016 -3.276 2017 1.323 2018 1.784 2019 1.221 2020 -3.277 2021 4.763 2022 3.017 2023 2.908 2024 2.154 2025 2.123 2026 2.083 2027 1.998 2028 2.001 2029 1.999