Year	Percent change (Units)
1980	8.098
1981	8.964
1982	1.924
1983	16.190
1984	18.156
1985	2.068
1986	28.558
1987	20.326
1988	6.540
1989	4.875
1990	0.367
1991	13.280
1992	6.731
1993	6.763
1994	6.120
1995	12.790
1996	6.965
1997	8.361
1998	1.989
1999	12.213
2000	17.698
2001	-8.337
2002	11.128
2003	10.931
2004	14.397
2005	6.026
2006	11.798
2007	9.830
2008	3.080
2009	-10.127
2010	27.620
2011	5.960
2012	21.192
2013	0.962
2014	2.699
2015	-2.129
2016	-4.869
2017	6.311
2018	0.471
2019	2.068
2020	0.060
2021	18.437
2022	-0.880
2023	-2.743
2024	4.050
2025	3.100
2026	3.000
2027	2.270
2028	3.350
2029	2.980