Year	Percent change (Units)
1980	4.429
1981	2.277
1982	0.948
1983	1.574
1984	3.351
1985	3.107
1986	5.824
1987	5.369
1988	4.064
1989	3.414
1990	4.282
1991	2.372
1992	4.353
1993	5.710
1994	5.147
1995	5.202
1996	2.056
1997	3.430
1998	0.570
1999	-4.204
2000	2.925
2001	1.678
2002	2.504
2003	3.918
2004	5.333
2005	4.447
2006	6.717
2007	6.738
2008	3.283
2009	1.140
2010	4.495
2011	6.948
2012	3.913
2013	5.134
2014	4.499
2015	2.956
2016	2.088
2017	1.359
2018	2.564
2019	3.187
2020	-7.186
2021	10.801
2022	7.289
2023	0.612
2024	1.140
2025	2.470
2026	3.000
2027	3.000
2028	3.000
2029	3.000