Year	Percent change (Units)
1980	2.406
1981	-4.400
1983	4.200
1984	6.000
1985	3.500
1986	2.900
1987	4.083
1988	6.129
1989	0.042
1990	-3.450
1991	12.084
1992	11.403
1993	10.969
1994	10.511
1995	10.364
1996	11.208
1997	7.274
1998	4.691
1999	2.181
2000	3.055
2001	4.206
2002	13.666
2003	2.990
2004	10.953
2005	15.029
2006	11.548
2007	14.010
2008	11.166
2009	0.859
2010	4.859
2011	3.472
2012	8.542
2013	4.955
2014	4.823
2015	0.944
2016	-2.580
2017	-0.150
2018	-1.316
2019	-0.702
2020	-5.638
2021	1.199
2022	3.045
2023	0.470
2024	2.558
2025	3.128
2026	3.395
2027	3.498
2028	3.566
2029	3.629