Year	Percent change (Units)
1980	0.624
1981	-4.186
1982	-2.612
1983	-0.182
1984	1.754
1985	10.796
1986	-3.233
1987	5.731
1988	8.799
1989	0.039
1990	-0.720
1991	0.304
1992	6.454
1993	11.040
1994	1.192
1995	10.520
1996	5.372
1997	5.151
1998	1.980
1999	1.385
2000	8.947
2001	0.815
2002	-0.809
2003	-1.762
2004	4.158
2005	8.802
2006	6.987
2007	7.459
2008	2.036
2009	-18.517
2010	8.702
2011	3.456
2012	0.106
2013	3.645
2014	3.193
2015	3.304
2016	-0.607
2017	0.534
2018	3.658
2019	-3.381
2020	-6.278
2021	11.311
2022	4.030
2023	3.530
2024	3.470
2025	3.565
2026	3.685
2027	3.685
2028	3.685
2029	3.685