Year	Percent change (Units)
1980	4.437
1981	-6.807
1982	-0.895
1983	-3.377
1984	12.855
1985	3.867
1986	6.708
1987	12.760
1988	7.483
1989	9.054
1990	6.254
1991	4.804
1992	3.766
1993	-10.650
1994	12.156
1995	11.581
1996	-1.245
1997	11.013
1998	8.689
1999	5.777
2000	12.277
2001	1.717
2002	0.470
2003	1.278
2004	5.767
2005	2.863
2006	7.781
2007	4.221
2008	-3.843
2009	-13.510
2010	14.371
2011	0.796
2012	-8.836
2013	-2.900
2014	3.294
2015	8.008
2016	3.900
2017	5.625
2018	3.288
2019	-0.842
2020	-8.654
2021	15.579
2022	9.578
2023	-1.601
2024	-0.561
2025	0.938
2026	1.100
2027	1.500
2028	1.500
2029	1.500