Year Percent change 1981 0.795 1982 4.059 1983 -6.067 1984 10.265 1985 1.151 1986 0.414 1987 -1.339 1988 3.445 1989 -0.202 1990 1.112 1991 2.1 1992 2.51 1993 2.888 1994 54.008 1995 3.124 1996 6.914 1997 2.435 1998 6.404 1999 -3.259 2000 9.841 2001 2.318 2002 1.247 2003 0.758 2004 2.668 2005 3.709 2006 5.264 2007 0.286 2008 8.377 2009 -0.459 2010 4.018 2011 1.827 2012 6.77 2013 -1.838 2014 -0.761 2015 2.301 2016 -2.652 2017 2.982 2018 0.968 2019 1.969 2020 1.919 2021 1.919 2022 1.919 2023 1.919 2024 1.919