Year Percent change 1980 2.314 1981 -0.099 1982 1.908 1983 2.804 1984 0.332 1985 2.243 1986 2.341 1987 1.681 1988 0.961 1989 3.887 1990 4.346 1991 3.442 1992 2.094 1993 0.527 1994 2.402 1995 2.668 1996 2.398 1997 2.094 1998 3.581 1999 3.556 2000 3.376 2001 1.267 2002 1.652 2003 0.941 2004 2.735 2005 2.244 2006 3.454 2007 3.727 2008 1.46 2009 -3.765 2010 1.837 2011 2.923 2012 0.68 2013 0.026 2014 0.661 2015 1.143 2016 2.04 2017 2.551 2018 2.713 2019 1.976 2020 1.7 2021 1.55 2022 1.46 2023 1.46 2024 1.46