Year	Percent change (Units)
1980	-8.995
1981	1.293
1982	-13.122
1983	1.904
1984	-6.066
1985	-18.742
1986	19.132
1987	1.105
1988	6.709
1989	24.610
1990	11.068
1991	7.294
1992	1.113
1993	5.305
1994	15.097
1995	9.118
1996	4.069
1997	-2.110
1998	0.000
1999	0.314
2000	4.908
2001	2.521
2002	5.248
2003	6.454
2004	6.469
2005	6.903
2006	-9.949
2007	-15.911
2008	29.124
2009	6.470
2010	28.526
2011	-25.990
2012	25.810
2013	6.646
2014	7.858
2015	-22.773
2016	-15.354
2017	9.007
2018	4.590
2019	2.731
2020	-19.261
2021	33.546
2022	12.084
2023	-8.372
2024	-2.010
2025	4.577
2026	2.670
2027	1.696
2028	1.972
2029	1.979