Year	Percent change (Units)
1980	7.296
1981	0.782
1982	3.454
1983	3.471
1984	3.488
1985	3.505
1986	3.521
1987	3.537
1988	-13.013
1989	-9.582
1990	0.343
1991	9.358
1992	-3.162
1993	-4.100
1994	7.497
1995	6.300
1996	7.400
1997	12.700
1998	2.200
1999	3.000
2000	0.500
2001	0.844
2002	2.985
2003	1.690
2004	3.670
2005	2.466
2006	4.658
2007	2.595
2008	6.020
2009	4.339
2010	0.391
2011	1.761
2012	5.009
2013	4.631
2014	0.912
2015	3.168
2016	3.191
2017	0.449
2018	1.153
2019	0.400
2020	1.373
2021	1.969
2022	3.026
2023	4.500
2024	3.600
2025	3.000
2026	3.000
2027	3.000
2028	3.000
2029	3.000