Year	Percent change (Units)
1980	-4.041
1981	4.420
1982	3.080
1983	4.153
1984	0.950
1985	-0.900
1986	7.000
1987	7.700
1988	-3.993
1989	4.700
1990	4.875
1991	0.834
1992	2.778
1993	2.211
1994	1.875
1995	2.521
1996	0.236
1997	-1.641
1998	-1.210
1999	0.981
2000	0.776
2001	1.281
2002	0.675
2003	3.667
2004	1.324
2005	0.894
2006	2.899
2007	1.444
2008	-0.818
2009	-3.411
2010	-1.435
2011	1.426
2012	-0.501
2013	0.224
2014	0.575
2015	0.869
2016	1.498
2017	0.679
2018	1.827
2019	0.970
2020	-9.920
2021	4.601
2022	5.222
2023	2.200
2024	1.800
2025	1.700
2026	1.600
2027	1.600
2028	1.600
2029	1.600