Year	Percent change (Units)
1981	-7.544
1982	3.951
1983	2.559
1984	5.399
1985	8.605
1986	3.976
1987	6.881
1988	4.613
1989	6.153
1990	1.801
1991	-6.796
1992	1.185
1993	1.914
1994	14.834
1995	10.256
1996	2.394
1997	11.145
1998	11.013
1999	3.113
2000	12.632
2001	-4.301
2002	-0.436
2003	4.878
2004	7.796
2005	8.135
2006	9.370
2007	9.396
2008	2.093
2009	-16.477
2010	16.228
2011	8.466
2012	-0.894
2013	-0.926
2014	5.225
2015	5.495
2016	5.450
2017	3.693
2018	4.789
2019	-0.395
2020	-3.675
2021	9.535
2022	2.555
2023	-2.919
2024	2.000
2025	2.000
2026	2.500
2027	3.000
2028	3.000
2029	3.000