Year	Percent change (Units)
1980	-2.285
1981	-3.419
1982	-3.708
1983	-5.156
1984	5.881
1985	3.717
1986	3.260
1987	-2.484
1988	10.124
1989	4.100
1990	5.897
1991	-0.590
1992	-3.207
1993	-16.319
1994	13.930
1995	19.691
1996	-3.871
1997	3.803
1998	-2.263
1999	2.540
2000	-0.970
2001	0.820
2002	3.830
2003	6.720
2004	-0.980
2005	-4.670
2006	2.650
2007	1.249
2008	4.036
2009	5.454
2010	5.854
2011	5.823
2012	6.303
2013	5.824
2014	5.633
2015	5.468
2016	5.734
2017	4.008
2018	4.795
2019	4.923
2020	1.976
2021	5.991
2022	5.811
2023	5.400
2024	5.300
2025	5.300
2026	5.500
2027	5.500
2028	5.500
2029	5.500