Year	Percent change (Units)
1980	9.317
1981	-1.636
1982	-2.302
1983	-3.337
1984	0.473
1985	-4.628
1986	7.845
1987	10.512
1988	17.036
1989	10.906
1990	7.735
1991	-7.558
1992	18.919
1993	-10.878
1994	7.042
1995	-20.225
1996	3.059
1997	3.517
1998	1.850
1999	8.931
2000	10.456
2001	2.177
2002	-4.093
2003	-1.394
2004	2.490
2005	2.051
2006	1.268
2007	5.280
2008	-0.650
2009	-4.654
2010	6.324
2011	7.015
2012	-0.575
2013	1.123
2014	6.292
2015	8.925
2016	7.220
2017	10.982
2018	7.220
2019	8.724
2020	1.636
2021	21.639
2022	13.618
2023	-1.494
2024	0.705
2025	1.804
2026	2.284
2027	2.718
2028	2.642
2029	2.642