Year	Percent change (Units)
1980	13.057
1981	13.333
1982	11.978
1983	9.460
1984	7.674
1985	5.831
1986	2.539
1987	3.289
1988	2.701
1989	6.569
1990	0.323
1991	3.406
1992	2.455
1993	2.234
1994	1.667
1995	1.768
1996	2.081
1997	1.267
1998	0.677
1999	0.575
2000	1.815
2001	1.784
2002	1.938
2003	2.169
2004	2.335
2005	1.888
2006	1.893
2007	1.608
2008	3.160
2009	0.101
2010	1.738
2011	2.287
2012	2.216
2013	0.990
2014	0.613
2015	0.086
2016	0.307
2017	1.166
2018	2.100
2019	1.297
2020	0.527
2021	2.068
2022	5.903
2023	5.662
2024	2.417
2025	1.792
2026	1.785
2027	1.818
2028	1.797
2029	1.714