Year	Percent change (Units)
1980	8.162
1981	3.815
1982	-0.085
1983	5.364
1984	10.165
1985	7.644
1986	11.493
1987	6.626
1988	5.214
1989	5.252
1990	3.012
1991	2.177
1992	1.158
1993	5.280
1994	6.676
1995	-4.360
1996	6.606
1997	5.471
1998	4.731
1999	3.709
2000	6.203
2001	-4.548
2002	1.028
2003	6.076
2004	5.767
2005	6.475
2006	12.707
2007	9.316
2008	-0.014
2009	-11.963
2010	-7.841
2011	-1.959
2012	3.372
2013	-0.601
2014	3.797
2015	3.824
2016	5.497
2017	3.144
2018	6.824
2019	4.344
2020	-17.503
2021	6.556
2022	8.459
2023	5.863
2024	6.077
2025	4.035
2026	2.760
2027	2.756
2028	2.769
2029	2.783