Year	Percent change (Units)
1980	0.395
1981	-5.245
1982	2.516
1983	3.694
1984	5.373
1985	4.571
1986	-0.215
1987	1.625
1988	3.177
1989	1.345
1990	5.692
1991	8.730
1992	-7.333
1993	9.692
1994	-10.313
1995	13.830
1996	9.979
1997	6.587
1998	1.061
1999	3.541
2000	0.775
2001	-4.076
2002	1.760
2003	5.706
2004	5.420
2005	3.269
2006	4.700
2007	9.600
2008	7.640
2009	8.328
2010	6.874
2011	4.854
2012	1.886
2013	5.200
2014	5.700
2015	2.950
2016	2.270
2017	4.000
2018	4.392
2019	5.448
2020	0.913
2021	4.567
2022	0.800
2023	1.600
2024	3.300
2025	3.800
2026	4.300
2027	4.500
2028	4.600
2029	4.600