Year	Percent change (Units)
1980	24.435
1981	18.925
1982	-10.433
1983	-0.434
1984	5.681
1985	0.919
1986	2.907
1987	9.517
1988	-39.385
1989	-7.571
1990	-4.100
1991	6.400
1992	7.700
1993	2.300
1994	7.066
1995	8.700
1996	-2.691
1997	6.799
1998	2.818
1999	2.891
2000	7.859
2001	8.434
2002	20.983
2003	7.971
2004	13.258
2005	1.594
2006	14.102
2007	2.501
2008	5.376
2009	-10.952
2010	12.638
2011	-0.853
2012	-1.211
2013	0.364
2014	6.187
2015	-7.308
2016	0.801
2017	2.541
2018	0.707
2019	11.986
2020	-15.806
2021	7.776
2022	18.437
2023	4.831
2024	0.623
2025	4.613
2026	3.609
2027	3.585
2028	3.604
2029	3.613