Year	Percent change (Units)
1980	5.451
1981	7.201
1982	3.748
1983	-0.511
1984	8.829
1985	7.464
1986	-1.204
1987	0.742
1988	5.689
1989	10.261
1990	11.355
1991	14.197
1992	-1.231
1993	-6.012
1994	8.003
1995	6.881
1996	6.060
1997	12.389
1998	7.069
1999	4.934
2000	14.488
2001	6.076
2002	4.229
2003	1.800
2004	10.380
2005	7.012
2006	12.833
2007	9.251
2008	1.267
2009	-14.273
2010	14.033
2011	8.528
2012	3.572
2013	1.183
2014	4.679
2015	4.880
2016	2.292
2017	5.559
2018	2.400
2019	2.297
2020	-10.032
2021	9.488
2022	3.451
2023	-1.655
2024	2.572
2025	3.651
2026	2.979
2027	3.072
2028	2.925
2029	2.775