Year	Percent change (Units)
1980	2.163
1981	3.503
1982	-3.166
1983	2.562
1984	5.899
1985	4.738
1986	2.121
1987	4.072
1988	4.411
1989	2.337
1990	0.203
1991	-2.091
1992	0.890
1993	2.658
1994	4.494
1995	2.682
1996	1.689
1997	4.280
1998	3.893
1999	5.141
2000	5.139
2001	1.875
2002	2.999
2003	1.806
2004	3.092
2005	3.210
2006	2.638
2007	2.050
2008	0.995
2009	-2.915
2010	3.091
2011	3.137
2012	1.756
2013	2.326
2014	2.873
2015	0.650
2016	1.039
2017	3.034
2018	2.743
2019	1.908
2020	-5.038
2021	5.287
2022	3.820
2023	1.066
2024	1.154
2025	2.308
2026	1.859
2027	1.683
2028	1.675
2029	1.660