Year	Percent change (Units)
1980	8.905
1981	7.650
1982	1.318
1983	0.785
1984	5.982
1985	6.058
1986	13.762
1987	-3.026
1988	5.461
1989	8.747
1990	6.982
1991	-4.222
1992	-0.575
1993	-3.460
1994	3.900
1995	6.752
1996	3.760
1997	12.862
1998	3.503
1999	2.028
2000	6.168
2001	1.696
2002	-2.825
2003	1.875
2004	2.318
2005	10.908
2006	3.373
2007	6.200
2008	5.998
2009	-5.934
2010	8.352
2011	9.209
2012	-5.541
2013	16.468
2014	-11.701
2015	2.902
2016	5.735
2017	-2.176
2018	1.331
2019	-0.945
2020	-1.682
2021	4.415
2022	7.224
2023	-1.230
2024	1.926
2025	3.654
2026	4.000
2027	4.000
2028	4.000
2029	4.000