Year	Percent change (Units)
1980	-36.410
1981	-2.398
1982	6.061
1983	-1.891
1984	-11.663
1985	28.849
1986	0.992
1987	-8.424
1988	1.533
1989	-11.734
1990	17.853
1991	3.240
1992	15.023
1993	5.573
1994	9.477
1995	1.222
1996	-3.783
1997	11.621
1998	-2.912
1999	-14.294
2000	7.871
2001	2.037
2002	-5.814
2003	0.078
2004	15.541
2005	15.784
2006	14.222
2007	16.973
2008	12.235
2009	-1.509
2010	4.735
2011	23.714
2012	5.561
2013	-5.529
2014	-8.702
2015	-4.841
2016	-3.273
2017	5.188
2018	1.648
2019	-0.096
2020	-27.733
2021	26.867
2022	29.284
2023	12.086
2024	-4.299
2025	4.421
2026	4.478
2027	1.689
2028	4.833
2029	3.588