Year	Percent change (Units)
1980	-2.186
1981	29.245
1982	2.533
1983	0.975
1984	-12.638
1985	-5.857
1986	16.770
1987	9.364
1988	0.541
1989	-39.187
1990	13.900
1991	-5.900
1992	29.900
1993	6.100
1994	-2.629
1995	-3.100
1996	7.740
1997	-2.331
1998	-5.459
1999	-1.184
2000	20.812
2001	3.201
2002	3.017
2003	2.159
2004	22.615
2005	16.155
2006	0.571
2007	4.068
2008	2.639
2009	-3.952
2010	-11.338
2011	-1.699
2012	8.714
2013	4.458
2014	0.839
2015	-3.655
2016	-6.209
2017	9.116
2018	-1.609
2019	2.573
2020	-9.059
2021	17.270
2022	1.928
2023	4.333
2024	2.765
2025	3.094
2026	3.026
2027	3.086
2028	3.109
2029	3.153