Year	Percent change (Units)
1980	-0.560
1981	1.878
1982	1.780
1983	-1.576
1984	1.700
1985	-6.740
1986	0.132
1987	2.382
1988	2.058
1989	4.952
1990	1.611
1991	-7.993
1992	-9.646
1993	0.054
1994	3.500
1995	-10.025
1996	-24.787
1997	-17.596
1998	-0.837
1999	-8.122
2000	3.807
2001	18.170
2002	26.425
2003	9.327
2004	6.598
2005	4.505
2006	4.224
2007	8.058
2008	5.400
2009	3.187
2010	5.347
2011	6.312
2012	15.178
2013	20.720
2014	4.555
2015	-20.493
2016	6.354
2017	3.765
2018	3.465
2019	5.254
2020	-1.969
2021	4.105
2022	3.458
2023	3.392
2024	4.005
2025	4.520
2026	4.518
2027	4.476
2028	4.490
2029	4.532