Year	Percent change (Units)
1980	3.997
1982	0.961
1983	7.845
1984	-2.305
1985	-11.413
1986	9.693
1987	13.870
1988	0.574
1989	-0.457
1990	2.602
1991	-7.218
1992	-8.907
1993	13.363
1994	3.486
1995	6.121
1996	13.533
1997	2.840
1998	-4.185
1999	6.294
2000	9.838
2001	7.400
2002	1.600
2003	-2.100
2004	11.700
2005	12.600
2006	11.500
2007	11.800
2008	11.200
2009	10.000
2010	10.600
2011	11.400
2012	8.700
2013	9.900
2014	10.300
2015	10.400
2016	8.000
2017	10.210
2018	7.703
2019	9.037
2020	6.057
2021	6.265
2022	6.358
2023	7.176
2024	6.234
2025	6.491
2026	6.691
2027	6.790
2028	6.985
2029	7.012