Year	Percent change (Units)
1980	-17.031
1981	-24.300
1982	7.300
1983	-15.400
1984	25.200
1985	0.300
1986	34.500
1987	4.700
1988	38.300
1989	8.000
1990	29.200
1991	2.000
1992	-13.412
1993	25.584
1994	6.863
1995	44.354
1996	-12.764
1997	-10.864
1998	-8.932
1999	-24.539
2000	-9.103
2001	-25.863
2002	-21.480
2003	-1.795
2004	15.096
2005	6.851
2006	14.917
2007	20.981
2008	21.552
2009	-20.804
2010	28.642
2011	14.768
2012	-10.473
2013	14.781
2014	-5.970
2015	-10.635
2016	0.669
2017	10.047
2018	-1.681
2019	-10.109
2020	-16.103
2021	1.886
2022	-4.668
2023	33.098
2024	2.619
2025	4.036
2026	2.188
2027	2.144
2028	1.882
2029	2.443