Year	Percent change (Units)
1980	1.594
1981	1.994
1982	2.236
1983	-1.511
1984	-18.323
1985	-12.774
1986	3.488
1987	17.604
1988	12.893
1989	21.902
1990	6.039
1991	-3.431
1992	7.773
1993	12.597
1994	15.609
1995	11.557
1996	12.334
1997	7.317
1998	-11.194
1999	-14.927
2000	22.464
2001	0.927
2002	5.585
2003	7.343
2004	2.184
2005	6.502
2006	2.808
2007	0.583
2008	6.870
2009	-9.418
2010	17.475
2011	1.154
2012	10.805
2013	-3.713
2014	11.527
2015	4.267
2016	22.361
2017	19.358
2018	11.807
2019	-2.491
2020	-20.010
2021	18.121
2022	13.294
2023	-3.329
2024	5.167
2025	9.678
2026	8.989
2027	9.391
2028	9.018
2029	3.221