Year	Percent change (Units)
1980	-0.708
1981	1.864
1982	28.568
1983	9.190
1984	-9.429
1985	-9.206
1986	15.754
1987	-9.671
1988	7.429
1989	8.833
1990	9.660
1991	6.225
1992	-4.987
1993	-7.520
1994	-0.294
1995	23.562
1996	-14.046
1997	-9.858
1998	11.804
1999	2.700
2000	-22.914
2001	4.450
2002	8.060
2003	17.296
2004	12.573
2005	2.054
2006	-14.103
2007	25.003
2008	-1.974
2009	4.281
2010	-1.678
2011	12.831
2012	2.224
2013	11.730
2014	4.112
2015	-2.230
2016	4.638
2017	10.741
2018	10.379
2019	9.393
2020	-12.852
2021	24.877
2022	-3.491
2023	3.846
2024	18.262
2025	19.988
2026	8.647
2027	8.228
2028	8.826
2029	7.888