Year	Percent change (Units)
1980	7.056
1981	-1.797
1982	-1.670
1983	3.891
1984	0.170
1985	-3.132
1986	22.473
1987	6.023
1988	10.021
1989	3.792
1990	-6.786
1991	2.715
1992	9.934
1993	-12.797
1994	-1.983
1995	15.243
1996	5.270
1997	-4.378
1998	-16.133
1999	9.592
2000	-42.617
2001	-24.334
2002	9.583
2003	18.655
2004	21.025
2005	5.996
2006	-0.412
2007	13.191
2008	22.524
2009	-20.997
2010	27.627
2011	49.101
2012	27.075
2013	1.547
2014	6.279
2015	2.238
2016	-6.687
2017	13.653
2018	13.478
2019	-15.742
2020	-18.939
2021	-11.883
2022	-10.230
2023	27.708
2024	-11.313
2025	7.629
2026	5.926
2027	6.500
2028	1.687
2029	1.745