Year Percent change 1980 1.523 1981 2.2 1982 16.928 1983 4.686 1984 -0.32 1985 -0.2 1986 0.7 1987 1.1 1988 2.6 1989 0.9 1990 127.9 1991 161.121 1992 210.386 1993 256.105 1994 136.742 1995 32.272 1996 38.809 1997 154.763 1998 59.097 1999 45.804 2000 45.667 2001 34.454 2002 22.498 2003 15.37 2004 11.855 2005 8.995 2006 6.591 2007 4.834 2008 7.846 2009 5.584 2010 6.113 2011 5.795 2012 3.339 2013 4.002 2014 1.076 2015 -0.596 2016 -1.555 2017 1.344 2018 4.631 2019 3.275 2020 2.952 2021 2.774 2022 2.549 2023 2.549 2024 2.549