Year	Percent change (Units)
1981	14.660
1982	13.243
1983	14.558
1984	2.604
1985	10.457
1986	2.411
1987	-6.986
1988	-3.934
1989	0.645
1990	-1.057
1991	-0.763
1992	0.000
1993	-4.769
1994	44.750
1995	5.022
1996	4.608
1997	0.358
1998	-2.984
1999	-4.212
2000	8.050
2001	2.559
2002	9.466
2003	-1.738
2004	-0.235
2005	1.529
2006	7.059
2007	-0.137
2008	14.525
2009	-1.159
2010	2.261
2011	4.342
2012	5.926
2013	2.566
2014	14.019
2015	10.661
2016	-4.466
2017	7.171
2018	4.605
2019	-2.041
2020	1.837
2021	2.701
2022	7.584
2023	4.023
2024	5.000
2025	4.200
2026	3.500
2027	3.000
2028	3.000
2029	3.000