Year	Percent change (Units)
1980	1.038
1981	1.013
1982	5.719
1983	8.564
1984	4.289
1985	19.553
1986	8.200
1987	-3.267
1988	-0.176
1989	5.178
1990	-6.406
1991	0.795
1992	-2.716
1993	-24.393
1994	5.985
1995	35.324
1996	0.758
1997	31.117
1998	18.169
1999	-13.732
2000	12.912
2001	-8.344
2002	-20.048
2003	-7.695
2004	-7.706
2005	42.687
2006	-2.470
2007	15.006
2008	11.977
2009	-6.056
2010	-10.487
2011	-1.760
2012	18.871
2013	-0.387
2014	11.462
2015	-0.526
2016	8.845
2017	1.749
2018	-3.257
2019	-2.577
2020	-21.700
2021	13.975
2022	-3.023
2023	16.959
2024	6.381
2025	4.825
2026	4.005
2027	4.091
2028	3.488
2029	3.421