Year	Percent change (Units)
1980	15.631
1981	10.008
1982	-2.087
1983	9.479
1984	14.805
1985	6.431
1986	13.558
1987	31.749
1988	26.768
1989	8.925
1990	11.536
1991	19.133
1992	22.306
1993	13.031
1994	13.671
1995	13.801
1996	4.313
1997	7.262
1998	-6.942
1999	-0.055
2000	20.192
2001	-1.450
2002	8.530
2003	15.480
2004	15.182
2005	9.166
2006	9.409
2007	9.852
2008	3.733
2009	-6.954
2010	19.880
2011	6.663
2012	4.575
2013	9.919
2014	1.475
2015	-2.673
2016	0.708
2017	7.272
2018	4.723
2019	-8.246
2020	-3.184
2021	17.162
2022	-13.250
2023	-8.615
2024	4.311
2025	4.111
2026	3.967
2027	3.963
2028	3.900
2029	3.906