Year Percent change (Units) 1980 6.002 1981 10.344 1982 0.826 1983 1.144 1984 0.912 1985 0.687 1986 -1.377 1987 1.526 1988 1.406 1989 3.311 1990 3.819 1991 2.875 1992 1.790 1993 2.554 1994 2.875 1995 0.842 1996 2.000 1997 2.048 1998 -1.429 1999 0.677 2000 2.063 2001 -0.588 2002 0.436 2003 0.745 2004 1.311 2005 1.260 2006 0.809 2007 3.820 2008 5.366 2009 -0.527 2010 4.590 2011 5.534 2012 4.324 2013 1.499 2014 -0.076 2015 -0.639 2016 0.163 2017 0.375 2018 0.465 2019 0.761 2020 0.024 2021 3.951 2022 6.460 2023 3.739 2024 2.900 2025 2.500 2026 1.978 2027 1.984 2028 1.984 2029 1.964