Year	Percent change (Units)
1980	14.509
1981	22.797
1982	0.932
1983	-2.200
1984	5.700
1985	-13.030
1986	-2.060
1987	-3.447
1988	16.141
1989	18.547
1990	9.602
1991	-7.875
1992	13.112
1993	6.709
1994	-1.058
1995	6.290
1996	-2.487
1997	8.697
1998	5.351
1999	5.814
2000	6.464
2001	15.048
2002	-2.909
2003	-2.136
2004	7.184
2005	-1.177
2006	5.660
2007	8.599
2008	4.785
2009	-4.632
2010	15.427
2011	-3.778
2012	8.414
2013	-1.492
2014	2.974
2015	-2.564
2016	5.155
2017	3.422
2018	0.954
2019	-8.566
2020	-15.005
2021	8.448
2022	11.674
2023	4.211
2024	6.000
2025	5.600
2026	5.000
2027	1.500
2028	0.500
2029	1.500