Year	Percent change (Units)
1980	12.259
1981	7.556
1982	12.058
1983	8.346
1984	4.847
1985	7.054
1986	-2.700
1987	-2.850
1988	4.191
1989	-0.322
1990	-0.807
1991	2.502
1992	-1.991
1993	0.614
1994	24.720
1995	7.772
1996	6.109
1997	2.929
1998	4.911
1999	-1.080
2000	-0.169
2001	4.727
2002	2.300
2003	2.040
2004	-0.400
2005	6.409
2006	2.336
2007	-0.233
2008	10.668
2009	0.864
2010	-0.608
2011	2.769
2012	3.817
2013	0.525
2014	-0.258
2015	1.653
2016	0.441
2017	1.483
2018	1.956
2019	-3.233
2020	1.885
2021	3.908
2022	13.779
2023	0.942
2024	2.100
2025	2.000
2026	2.000
2027	2.000
2028	2.000
2029	2.000