Year	Percent change (Units)
1980	15.495
1981	3.269
1982	4.258
1983	2.094
1984	1.457
1985	0.926
1986	0.369
1987	0.436
1988	0.851
1989	0.287
1990	0.496
1991	0.787
1992	1.649
1993	0.954
1994	1.323
1995	0.840
1996	2.313
1997	-0.452
1998	1.362
1999	1.523
2000	0.706
2001	0.000
2002	1.753
2003	-0.200
2004	1.605
2005	3.356
2006	2.197
2007	6.355
2008	6.766
2009	1.893
2010	4.927
2011	6.313
2012	4.634
2013	3.737
2014	0.970
2015	0.294
2016	1.463
2017	0.481
2018	0.158
2019	-0.064
2020	-1.575
2021	2.624
2022	2.075
2023	1.921
2024	2.243
2025	2.000
2026	2.000
2027	2.000
2028	2.000
2029	2.000