Year Percent change 1980 9.87 1981 17.286 1982 -22.498 1983 3.097 1984 5.626 1985 4.884 1986 38.784 1987 30.28 1988 42.837 1989 -2.743 1990 10.812 1991 10.812 1992 10.812 1993 10.812 1994 5.677 1995 9.813 1996 10.201 1997 21.148 1998 24.791 1999 11.032 2000 -4.329 2001 3.571 2002 5.225 2003 3.707 2004 11.533 2005 10.762 2006 9.045 2007 15.912 2008 3.426 2009 -13.117 2010 8.518 2011 5.97 2012 3.155 2013 4.156 2014 3.886 2015 3.875 2016 3.698 2017 5.529 2018 2.272 2019 4.59 2020 3.925 2021 3.899 2022 3.413 2023 3.244 2024 3.22