Year	Percent change (Units)
1980	12.500
1981	-19.700
1982	-17.500
1983	-18.100
1984	17.900
1985	-7.100
1986	16.800
1987	13.300
1988	9.000
1990	4.750
1991	-8.039
1992	-0.719
1993	-12.255
1994	25.674
1995	32.069
1996	2.163
1997	1.122
1998	-3.198
1999	-7.187
2000	6.759
2001	11.454
2002	-3.821
2003	1.293
2004	7.510
2005	14.733
2006	10.110
2007	17.300
2008	0.221
2009	13.765
2010	0.626
2011	8.415
2012	1.612
2013	1.906
2014	8.407
2015	-2.521
2016	-9.065
2017	10.275
2018	-3.425
2019	4.217
2020	-2.435
2021	13.752
2022	3.681
2023	-11.870
2024	8.236
2025	5.898
2026	8.298
2027	6.821
2028	6.662
2029	6.664