Year	Percent change (Units)
1980	4.402
1981	3.589
1982	1.866
1983	0.576
1984	-0.676
1985	-2.309
1986	-3.121
1987	-2.394
1988	-0.350
1989	1.212
1990	-1.056
1991	3.880
1992	-1.028
1993	1.241
1994	1.363
1995	5.136
1996	0.270
1997	-0.246
1998	-0.422
1999	-2.123
2000	-1.035
2001	-1.119
2002	0.111
2003	0.479
2004	0.294
2005	0.573
2006	1.904
2007	4.976
2008	6.121
2009	4.262
2010	3.698
2011	3.744
2012	2.866
2013	3.530
2014	2.236
2015	1.206
2016	2.069
2017	-0.838
2018	2.458
2019	-2.093
2020	3.445
2021	3.063
2022	2.474
2023	2.327
2024	2.257
2025	2.033
2026	2.004
2027	2.000
2028	2.000
2029	1.996