Year Percent change 1980 38.358 1981 45.53 1982 0.36 1983 -16.74 1984 -3.887 1985 -12.498 1986 24.839 1987 13.786 1988 -10.536 1989 -15.523 1990 6.525 1991 23.064 1992 5.113 1993 3.259 1994 29.926 1995 28.424 1996 -0.881 1997 13.204 1998 2.415 1999 -18.045 2000 4.2 2001 0.971 2002 4.333 2003 3.529 2004 7.637 2005 10.41 2006 15.452 2007 20.669 2008 24.598 2009 -17.486 2010 27.198 2011 13.477 2012 10.364 2013 3.818 2014 -1.619 2015 0.183 2016 -3.014 2017 4.54 2018 1.572 2019 4.281 2020 5.273 2021 5.52 2022 4.336 2023 4.34 2024 4.072