Year	Percent change (Units)
1981	7.817
1982	-0.319
1983	3.238
1984	7.006
1985	1.586
1986	3.202
1987	1.594
1988	3.452
1989	1.242
1990	1.700
1991	-16.908
1992	0.581
1993	-1.094
1994	17.800
1995	6.835
1996	10.407
1997	14.221
1998	11.839
1999	3.712
2000	14.150
2001	2.665
2002	5.291
2003	5.125
2004	8.365
2005	8.720
2006	7.996
2007	7.370
2008	3.780
2009	-20.670
2010	9.596
2011	8.259
2012	-1.987
2013	1.132
2014	-0.270
2015	-0.287
2016	6.368
2017	5.210
2018	3.843
2019	0.030
2020	-3.473
2021	6.672
2022	5.196
2023	-11.255
2024	2.500
2025	3.100
2026	3.500
2027	3.500
2028	3.500
2029	3.500