Year Percent change 1987 -34.571 1988 266.652 1989 34.668 1990 66.253 1991 67.589 1992 17.605 1993 5.28 1994 14.528 1995 29.864 1996 9.208 1997 -0.166 1998 -12.845 1999 -0.307 2000 -0.632 2001 0.925 2002 4.119 2003 3.083 2004 9.822 2005 8.819 2006 6.699 2007 12.631 2008 19.891 2009 6.518 2010 11.748 2011 18.127 2012 6.816 2013 6.036 2014 1.839 2015 0.597 2016 4.737 2017 2.597 2018 2.983 2019 3.2 2020 3.4 2021 3.5 2022 3.6 2023 3.8 2024 4