Year Percent change (Units) 1980 -38.309 1981 122.650 1982 72.791 1983 8.355 1984 -5.498 1985 46.863 1986 -8.151 1987 -11.745 1988 28.826 1989 14.879 1990 34.794 1991 17.500 1992 37.300 1993 81.400 1994 24.900 1995 4.300 1996 2.601 1997 -1.416 1998 6.400 1999 1.504 2000 7.193 2001 -17.197 2002 -10.829 2003 -1.570 2004 4.621 2005 14.064 2006 20.741 2007 5.173 2008 15.360 2009 6.900 2010 16.547 2011 27.348 2012 8.019 2013 8.252 2014 27.331 2015 -6.595 2016 20.182 2017 10.325 2018 10.270 2019 5.950 2020 3.964 2021 10.213 2022 -1.770 2023 5.862 2024 1.315 2025 1.368 2026 2.878 2027 3.201 2028 5.529 2029 5.655