Year	Percent change (Units)
1980	7.345
1981	1.056
1982	-2.797
1983	-1.500
1984	0.201
1985	0.757
1986	0.273
1987	-0.432
1988	0.559
1989	-1.131
1990	-0.440
1991	1.262
1992	-2.251
1993	-4.922
1994	-11.603
1995	9.892
1996	4.143
1997	2.705
1998	2.182
1999	2.710
2000	0.870
2001	-0.343
2002	1.052
2003	3.481
2004	-1.318
2005	3.072
2006	1.769
2007	4.707
2008	2.658
2009	5.890
2010	-5.652
2011	5.098
2012	0.502
2013	4.325
2014	1.723
2015	2.563
2016	1.812
2017	2.510
2018	1.668
2019	-1.685
2020	-3.343
2021	-1.798
2022	-1.682
2023	-1.864
2024	-3.000
2025	1.500
2026	1.500
2027	1.500
2028	1.500
2029	1.500