Year Percent change 1981 -0.498 1982 4.2 1983 -3.4 1984 5.5 1985 4.3 1986 -1 1987 5.6 1988 1.958 1989 2.925 1990 4.58 1991 7.305 1992 3.095 1993 2.276 1994 2.963 1995 4.016 1996 3.747 1997 5.994 1998 -16.909 1999 13.228 2000 -0.189 2001 2.017 2002 -1.279 2003 0.402 2004 2.761 2005 4.266 2006 2.309 2007 3.263 2008 3.204 2009 3.369 2010 4.611 2011 8.085 2012 -1.713 2013 3.256 2014 0.965 2015 6.134 2016 6.263 2017 5.919 2018 3.8 2019 5 2020 5 2021 5 2022 5 2023 5 2024 5