Year	Percent change (Units)
1980	10.066
1981	7.946
1982	7.083
1983	1.297
1984	2.433
1985	3.500
1986	5.435
1987	5.498
1988	4.995
1989	2.792
1990	0.604
1991	3.400
1992	6.383
1993	5.273
1994	5.699
1995	4.330
1996	2.976
1997	2.966
1998	1.994
1999	2.100
2000	1.348
2001	2.800
2002	2.918
2003	3.119
2004	5.041
2005	6.195
2006	9.285
2007	11.128
2008	12.258
2009	-4.725
2010	0.879
2011	0.876
2012	0.663
2013	1.104
2014	2.346
2015	4.068
2016	1.619
2017	1.966
2018	3.071
2019	-1.934
2020	-2.076
2021	-0.113
2022	4.827
2023	1.623
2024	2.100
2025	2.000
2026	2.000
2027	2.000
2028	2.000
2029	2.000