Year	Percent change (Units)
1980	3.700
1981	0.644
1982	-3.542
1983	-2.528
1984	0.510
1985	-0.600
1986	0.100
1987	3.579
1988	3.892
1989	3.943
1990	3.101
1991	3.000
1992	4.600
1993	3.400
1994	3.500
1995	4.400
1996	2.800
1997	4.100
1998	4.600
1999	3.700
2000	2.500
2001	3.104
2002	3.839
2003	2.560
2004	3.138
2005	3.276
2006	5.351
2007	6.338
2008	3.294
2009	0.477
2010	2.884
2011	4.164
2012	2.975
2013	3.695
2014	4.444
2015	4.092
2016	2.678
2017	3.080
2018	3.407
2019	4.018
2020	-1.792
2021	8.002
2022	4.118
2023	3.474
2024	3.500
2025	3.700
2026	3.710
2027	3.760
2028	3.860
2029	3.860