Year	Percent change (Units)
1980	5.240
1981	7.714
1982	4.078
1983	5.682
1984	7.754
1985	9.610
1986	-2.729
1987	2.119
1988	9.600
1989	10.265
1990	8.453
1991	3.215
1992	2.608
1993	-3.391
1994	8.291
1995	12.037
1996	6.960
1997	15.559
1998	8.195
1999	7.804
2000	13.368
2001	6.005
2002	4.281
2003	0.049
2004	10.605
2005	6.054
2006	7.929
2007	8.415
2008	0.876
2009	-16.637
2010	18.357
2011	6.289
2012	0.883
2013	-0.804
2014	2.883
2015	3.136
2016	2.854
2017	4.903
2018	4.792
2019	3.554
2020	-7.702
2021	12.273
2022	7.068
2023	2.708
2024	1.827
2025	4.521
2026	3.521
2027	2.621
2028	2.021
2029	2.221