Year Percent change 1981 9.521 1982 23.339 1983 29.701 1984 29.79 1985 33.893 1986 41.397 1987 185.325 1988 51.327 1989 28.38 1990 47.099 1991 35.214 1992 54.5 1993 43.638 1994 56.558 1995 56.537 1996 19.343 1997 6.197 1998 -0.956 1999 6.216 2000 11.438 2001 21.935 2002 9.119 2003 13.815 2004 9.067 2005 11.148 2006 9.374 2007 10.264 2008 11.817 2009 2.258 2010 17.44 2011 6.14 2012 2.016 2013 3.537 2014 1.927 2015 10.554 2016 23.666 2017 5.648 2018 3.524 2019 5.501 2020 5.501 2021 5.501 2022 5.501 2023 5.501 2024 5.501