Year	Percent change (Units)
1980	5.263
1981	8.452
1982	2.825
1983	9.521
1984	3.783
1985	8.642
1986	2.871
1987	4.309
1988	5.997
1989	5.698
1990	0.692
1991	1.404
1992	3.044
1993	7.311
1994	6.930
1995	7.492
1996	6.694
1997	7.639
1998	8.413
1999	11.860
2000	7.267
2001	6.138
2002	5.300
2003	7.502
2004	4.927
2005	5.810
2006	9.118
2007	15.200
2008	7.039
2009	-1.504
2010	1.836
2011	3.925
2012	1.084
2013	0.632
2014	0.697
2015	0.936
2016	4.281
2017	4.551
2018	3.707
2019	6.948
2020	-20.805
2021	5.615
2022	17.117
2023	4.792
2024	4.742
2025	4.732
2026	4.622
2027	4.586
2028	4.492
2029	4.507