Year	Percent change (Units)
1980	25.654
1981	-1.797
1982	-1.670
1983	3.891
1984	0.170
1985	-3.132
1986	4.188
1987	14.002
1988	28.270
1989	-16.840
1990	-25.624
1991	13.246
1992	-8.836
1993	13.549
1994	-2.189
1995	1.551
1996	-25.530
1997	7.111
1998	-35.829
1999	-17.474
2000	-22.182
2001	-14.704
2002	-22.708
2003	-1.687
2004	14.953
2005	53.472
2006	26.755
2007	25.501
2008	-5.695
2009	-2.543
2010	36.450
2011	4.001
2012	2.803
2013	6.974
2014	0.722
2015	11.205
2016	-1.429
2017	3.500
2018	7.485
2019	-3.583
2020	-13.182
2021	-5.040
2022	2.316
2023	9.387
2024	-8.456
2025	10.037
2026	7.725
2027	4.430
2028	3.131
2029	2.775