Year Percent change (Units) 1987 -31.248 1988 23.000 1989 63.800 1990 141.800 1991 191.000 1992 75.000 1993 114.319 1994 10.440 1995 10.077 1996 7.147 1997 10.503 1998 12.899 1999 1.996 2000 -0.826 2001 -0.117 2002 -0.036 2003 1.027 2004 3.925 2005 6.349 2006 6.143 2007 7.668 2008 24.997 2009 -0.663 2010 3.997 2011 5.480 2012 2.933 2013 2.944 2014 3.853 2015 1.215 2016 3.035 2017 2.906 2018 2.460 2019 1.944 2020 2.938 2021 2.921 2022 5.327 2023 2.143 2024 2.268 2025 3.040 2026 3.040 2027 3.000 2028 3.000 2029 3.000