Year	Percent change (Units)
1980	4.839
1981	5.769
1982	2.202
1983	5.004
1984	1.011
1985	12.905
1986	-2.331
1987	4.437
1988	2.655
1989	-1.229
1990	2.537
1991	-1.245
1992	33.002
1993	10.461
1994	16.808
1995	26.510
1996	52.678
1997	147.973
1998	24.815
1999	26.395
2000	110.505
2001	60.023
2002	19.621
2003	14.455
2004	30.391
2005	8.210
2006	6.501
2007	15.282
2008	17.799
2009	1.343
2010	-8.924
2011	6.524
2012	8.313
2013	-4.133
2014	0.415
2015	-9.110
2016	-8.816
2017	-5.668
2018	-6.237
2019	-5.482
2020	-4.788
2021	-0.377
2022	3.246
2023	-5.947
2024	0.467
2025	-4.583
2026	-3.157
2027	1.657
2028	-0.079
2029	2.947