Year Percent change (Units) 1980 -2.995 1981 12.954 1982 -3.572 1983 -6.027 1984 9.912 1985 3.733 1986 7.193 1987 0.000 1988 1.718 1989 3.790 1990 1.364 1991 -0.799 1992 -4.923 1993 -1.198 1994 12.572 1995 3.166 1996 -6.157 1997 4.105 1998 3.340 1999 2.887 2000 -3.581 2001 2.609 2002 2.091 2003 -2.249 2004 -0.096 2005 2.931 2006 4.754 2007 4.031 2008 2.613 2009 2.812 2010 4.631 2011 4.195 2012 5.054 2013 -36.392 2014 0.080 2015 4.338 2016 4.750 2017 4.528 2018 3.820 2019 2.970 2020 0.959 2021 0.983 2022 0.472 2023 0.727 2024 1.269 2025 1.720 2026 1.946 2027 2.111 2028 2.341 2029 2.551