Year	Percent change (Units)
1980	8.810
1981	8.682
1982	7.389
1983	5.879
1984	4.281
1985	1.753
1986	6.837
1987	6.978
1988	6.935
1989	0.986
1990	-0.658
1991	1.575
1992	4.218
1993	2.130
1994	25.956
1995	14.100
1996	2.700
1997	6.301
1998	4.503
1999	0.744
2000	2.534
2001	4.355
2002	3.080
2003	3.297
2004	1.459
2005	3.884
2006	2.466
2007	1.896
2008	1.706
2009	0.518
2010	1.751
2011	4.895
2012	1.300
2013	2.584
2014	0.490
2015	1.151
2016	0.649
2017	0.556
2018	0.624
2019	0.806
2020	2.415
2021	4.159
2022	5.208
2023	4.389
2024	3.800
2025	3.000
2026	2.200
2027	1.950
2028	2.000
2029	2.000