Year	Percent change (Units)
1980	4.408
1981	2.927
1982	-0.416
1983	6.513
1984	3.850
1985	10.167
1986	1.211
1987	-4.686
1988	2.511
1989	-0.858
1990	8.625
1991	13.012
1992	2.682
1993	4.301
1994	8.194
1995	2.789
1996	5.609
1997	6.175
1998	1.395
1999	4.322
2000	6.886
2001	2.130
2002	6.014
2003	4.080
2004	6.113
2005	0.083
2006	2.350
2007	5.986
2008	-1.071
2009	3.819
2010	4.942
2011	1.934
2012	4.428
2013	0.886
2014	2.579
2015	3.852
2016	1.588
2017	1.704
2018	2.679
2019	2.665
2020	-3.679
2021	4.045
2022	-3.902
2023	0.566
2024	1.494
2025	2.689
2026	4.512
2027	3.590
2028	3.802
2029	3.807