Year	Percent change (Units)
1980	-24.638
1981	-15.819
1982	1.714
1983	-0.899
1984	7.224
1985	2.471
1986	-5.904
1987	-5.975
1988	5.162
1989	25.187
1990	19.512
1991	-1.114
1992	2.553
1993	12.541
1994	4.489
1995	6.231
1996	2.430
1997	3.378
1998	-6.227
1999	-5.300
2000	-10.458
2001	-5.042
2002	-6.581
2003	9.188
2004	0.022
2005	-2.369
2006	-10.231
2007	2.919
2008	-1.966
2009	7.935
2010	9.342
2011	-12.501
2012	-12.399
2013	1.914
2014	-3.003
2015	18.522
2016	-3.595
2017	-3.599
2018	-6.262
2019	19.905
2020	6.084
2021	2.541
2022	-2.786
2023	-3.228
2024	3.502
2025	1.699
2026	2.292
2027	2.320
2028	1.645
2029	1.316