Year	Percent change (Units)
1980	6.079
1981	17.096
1982	11.501
1983	15.947
1984	13.904
1985	14.523
1986	2.145
1987	-3.992
1988	5.245
1989	2.983
1990	8.378
1991	6.044
1992	8.492
1993	6.144
1994	3.845
1995	4.831
1996	2.889
1997	6.178
1998	2.704
1999	0.298
2000	6.193
2001	4.613
2002	-0.784
2003	-2.195
2004	1.992
2005	2.780
2006	4.670
2007	4.980
2008	8.950
2009	5.982
2010	2.472
2011	2.894
2012	8.863
2013	5.227
2014	1.292
2015	5.017
2016	5.046
2017	0.304
2018	1.287
2019	-1.130
2020	-3.378
2021	3.092
2022	4.311
2023	1.311
2024	1.194
2025	3.088
2026	3.547
2027	3.236
2028	3.114
2029	3.185