Year Percent change (Units) 1980 40.039 1981 34.884 1982 37.069 1983 76.730 1984 52.630 1985 23.460 1986 46.730 1987 90.370 1988 82.749 1989 104.065 1990 81.295 1991 2154.440 1992 4129.170 1993 1986.900 1994 23773.100 1995 541.801 1996 617.000 1997 199.000 1998 29.145 1999 284.900 2000 550.000 2001 357.280 2002 25.316 2003 12.817 2004 4.001 2005 21.545 2006 12.845 2007 16.672 2008 17.966 2009 46.101 2010 23.461 2011 14.950 2012 0.857 2013 0.876 2014 1.240 2015 0.738 2016 3.193 2017 35.734 2018 29.266 2019 4.705 2020 11.358 2021 8.989 2022 9.266 2023 19.894 2024 17.247 2025 8.472 2026 6.952 2027 6.952 2028 6.952 2029 7.000