Year	Percent change (Units)
1980	-0.484
1981	-0.658
1982	3.678
1983	2.594
1984	4.172
1985	4.005
1986	4.900
1987	0.254
1988	-0.008
1989	0.642
1990	1.473
1991	1.397
1992	1.959
1993	0.008
1994	5.329
1995	3.029
1996	2.905
1997	3.260
1998	2.213
1999	2.948
2000	3.749
2001	0.823
2002	0.467
2003	0.388
2004	2.668
2005	2.342
2006	3.912
2007	0.908
2008	-0.511
2009	-4.905
2010	1.868
2011	1.336
2012	0.229
2013	0.935
2014	1.616
2015	2.343
2016	3.248
2017	2.819
2018	1.991
2019	1.493
2020	-2.423
2021	6.845
2022	2.731
2023	1.813
2024	2.130
2025	1.484
2026	1.460
2027	1.400
2028	1.400
2029	1.400