Year	Percent change (Units)
1980	0.953
1981	1.776
1982	-1.348
1983	5.761
1984	18.652
1985	4.540
1986	4.526
1987	3.202
1988	9.084
1989	0.893
1990	4.603
1991	1.666
1992	7.486
1993	10.794
1994	12.824
1995	8.869
1996	5.955
1997	8.631
1998	9.520
1999	10.792
2000	8.965
2001	-2.694
2002	1.200
2003	-1.692
2004	5.559
2005	2.281
2006	0.887
2007	1.084
2008	-4.554
2009	-12.950
2010	6.676
2011	4.797
2012	2.764
2013	2.453
2014	6.319
2015	3.399
2016	1.525
2017	1.491
2018	3.589
2019	2.275
2020	-8.992
2021	2.721
2022	3.232
2023	5.714
2024	3.189
2025	2.780
2026	3.446
2027	3.517
2028	3.340
2029	3.132