Year	Percent change (Units)
1981	11.285
1982	15.913
1983	12.382
1984	9.701
1985	11.681
1986	4.106
1987	-5.164
1988	-2.079
1989	0.809
1990	-0.909
1991	-0.718
1992	-0.496
1993	0.498
1994	37.539
1995	5.510
1996	2.494
1997	1.969
1998	0.908
1999	0.486
2000	1.366
2001	4.051
2002	1.500
2003	-1.488
2004	1.709
2005	1.422
2006	3.909
2007	6.178
2008	5.548
2009	-4.545
2010	4.294
2011	2.735
2012	1.134
2013	-0.076
2014	-0.808
2015	0.959
2016	2.859
2017	-0.792
2018	1.116
2019	0.638
2020	2.433
2021	3.825
2022	12.800
2023	0.788
2024	9.024
2025	-9.453
2026	30.253
2027	-1.777
2028	-0.003
2029	-0.236