Year Percent change (Units) 1980 -2.076 1981 0.562 1982 -8.884 1983 -11.497 1984 2.134 1985 0.366 1986 -0.234 1987 -0.130 1988 -5.981 1989 -4.944 1990 -3.010 1991 6.026 1992 7.758 1993 8.201 1994 8.482 1995 5.055 1996 7.956 1997 6.185 1998 -1.707 1999 2.986 2000 -1.345 2001 2.260 2002 1.149 2003 -0.652 2004 1.566 2005 -1.942 2006 5.127 2007 7.020 2008 1.977 2009 3.319 2010 4.371 2011 5.437 2012 5.039 2013 3.653 2014 1.686 2015 0.687 2016 3.807 2017 3.734 2018 4.441 2019 5.353 2020 43.480 2021 20.060 2022 62.288 2023 32.963 2024 33.895 2025 18.716 2026 21.058 2027 21.055 2028 13.486 2029 11.930