Year	Percent change (Units)
1980	-2.004
1981	7.229
1982	-33.315
1983	-10.636
1984	-12.714
1985	21.465
1986	5.917
1987	-10.972
1988	-11.155
1989	-5.429
1990	-5.107
1991	-19.127
1992	17.999
1993	6.166
1994	5.896
1995	4.224
1996	4.911
1997	3.975
1998	4.699
1999	-6.284
2000	-7.607
2001	4.349
2002	-1.470
2003	-2.660
2004	-4.148
2005	-4.276
2006	-1.070
2007	1.872
2008	-2.939
2009	10.255
2010	-1.905
2011	-3.478
2012	3.675
2013	-1.102
2014	0.491
2015	14.948
2016	4.490
2017	-1.966
2018	1.695
2019	11.517
2020	6.954
2021	3.118
2022	-6.493
2023	10.714
2024	0.596
2025	2.720
2026	0.211
2027	-1.368
2028	-0.060
2029	1.282