Year Percent change (Units) 1980 0.000 1981 0.000 1982 0.000 1983 0.000 1984 0.000 1985 0.000 1986 0.000 1987 0.000 1988 0.000 1989 0.000 1990 0.000 1991 15.465 1992 -7.076 1993 12.603 1994 -3.938 1995 -2.893 1996 -12.365 1997 -2.906 1998 -11.214 1999 33.676 2000 12.984 2001 -21.580 2002 6.545 2003 6.185 2004 9.182 2005 3.235 2006 8.730 2007 12.127 2008 4.050 2009 -12.106 2010 5.578 2011 6.188 2012 0.511 2013 2.835 2014 4.788 2015 5.246 2016 4.522 2017 5.510 2018 4.398 2019 4.081 2020 -4.933 2021 11.408 2022 4.392 2023 -0.874 2024 1.906 2025 3.704 2026 3.727 2027 3.760 2028 3.855 2029 3.821