Year	Percent change (Units)
1980	7.447
1981	7.375
1982	2.159
1983	1.195
1984	5.664
1985	6.106
1986	11.404
1987	-1.325
1988	5.819
1989	7.119
1990	5.842
1991	-3.456
1992	1.262
1993	-1.276
1994	4.600
1995	6.030
1996	3.668
1997	10.692
1998	4.960
1999	4.166
2000	7.991
2001	1.422
2002	-2.005
2003	0.900
2004	4.677
2005	9.513
2006	2.831
2007	5.992
2008	4.457
2009	-2.728
2010	7.872
2011	8.850
2012	-2.095
2013	12.473
2014	-6.693
2015	4.775
2016	5.230
2017	-0.292
2018	0.714
2019	0.290
2020	-3.014
2021	5.645
2022	5.997
2023	3.655
2024	2.914
2025	3.654
2026	4.000
2027	4.000
2028	4.000
2029	4.000