Year	Percent change (Units)
1980	-52.937
1981	21.801
1982	27.678
1983	-13.094
1984	-54.600
1985	134.000
1986	4.600
1987	-51.694
1988	99.134
1989	-6.490
1990	-10.241
1991	47.968
1992	-7.719
1993	20.197
1994	-16.940
1995	10.312
1996	-10.645
1997	4.517
1998	-28.721
1999	7.404
2000	11.241
2001	-22.051
2002	9.252
2003	-17.267
2004	21.807
2005	21.027
2006	6.520
2007	5.742
2008	-3.103
2009	-4.739
2010	14.004
2011	-1.837
2012	-10.382
2013	20.061
2014	24.162
2015	-7.418
2016	-1.712
2017	2.069
2018	12.876
2019	-0.459
2020	-49.669
2021	86.944
2022	42.490
2023	-3.692
2024	0.033
2025	7.555
2026	7.993
2027	6.286
2028	5.797
2029	6.882