Year	Percent change (Units)
1980	15.331
1981	-0.453
1982	9.372
1983	10.207
1984	4.871
1985	-16.250
1986	-6.469
1987	8.474
1988	24.517
1989	29.120
1990	21.700
1991	22.594
1992	5.708
1993	15.957
1994	26.158
1995	24.842
1996	5.211
1997	6.238
1998	-19.084
1999	12.659
2000	22.570
2001	-6.847
2002	4.460
2003	2.756
2004	19.281
2005	6.030
2006	14.411
2007	3.320
2008	-7.557
2009	-21.902
2010	12.117
2011	5.600
2012	-0.607
2013	1.826
2014	3.801
2015	1.693
2016	1.550
2017	8.464
2018	2.329
2019	-1.944
2020	-8.875
2021	24.776
2022	16.625
2023	-5.141
2024	8.602
2025	5.604
2026	3.742
2027	4.659
2028	5.049
2029	4.758