Year	Percent change (Units)
1980	-2.051
1981	-0.687
1982	1.965
1983	4.166
1984	2.220
1985	4.088
1986	3.108
1987	5.420
1988	5.377
1989	2.402
1990	0.560
1991	-1.405
1992	0.245
1993	2.259
1994	3.410
1995	2.386
1996	2.582
1997	4.925
1998	3.414
1999	3.066
2000	4.319
2001	2.579
2002	1.792
2003	3.147
2004	2.426
2005	2.739
2006	2.386
2007	2.620
2008	-0.226
2009	-4.615
2010	2.239
2011	1.145
2012	1.513
2013	1.792
2014	3.196
2015	2.220
2016	1.921
2017	2.655
2018	1.404
2019	1.642
2020	-10.360
2021	8.675
2022	4.345
2023	0.145
2024	0.460
2025	1.540
2026	1.726
2027	1.740
2028	1.597
2029	1.419