Year	Percent change (Units)
1980	7.325
1981	24.300
1982	10.400
1983	1.621
1984	8.412
1985	-1.070
1986	-3.245
1987	-6.638
1988	0.598
1989	-0.818
1990	-2.025
1991	1.499
1992	-5.912
1993	-0.326
1994	35.534
1995	10.858
1996	5.339
1997	2.930
1998	4.571
1999	-2.061
2000	2.704
2001	3.936
2002	2.505
2003	-1.476
2004	0.245
2005	7.810
2006	0.040
2007	0.054
2008	11.310
2009	0.455
2010	0.944
2011	2.930
2012	0.465
2013	2.285
2014	-0.890
2015	0.961
2016	0.179
2017	0.190
2018	2.753
2019	-2.520
2020	2.898
2021	3.838
2022	4.226
2023	3.701
2024	6.365
2025	4.580
2026	3.200
2027	2.000
2028	2.000
2029	2.000