Year	Percent change (Units)
1980	-4.809
1981	-4.311
1982	-4.667
1983	-7.620
1984	-0.791
1985	-7.568
1986	11.940
1987	-6.610
1988	-0.837
1989	39.899
1990	18.698
1991	-0.417
1992	-7.816
1993	15.901
1994	28.712
1995	10.779
1996	6.400
1997	2.000
1998	0.000
1999	0.314
2000	4.908
2001	2.521
2002	5.248
2003	6.454
2004	6.469
2005	6.903
2006	-9.949
2007	-15.911
2008	29.124
2009	6.470
2010	28.526
2011	-25.990
2012	25.810
2013	0.000
2014	7.858
2015	-22.773
2016	-15.354
2017	9.007
2018	4.590
2019	2.731
2020	-19.261
2021	33.546
2022	12.084
2023	-8.372
2024	-2.010
2025	4.577
2026	2.670
2027	1.696
2028	1.972
2029	1.979