Year	Percent change (Units)
1980	0.610
1981	0.300
1982	-3.939
1983	-4.042
1984	-0.201
1985	-1.676
1986	-2.574
1987	2.463
1988	2.910
1989	3.790
1990	4.636
1991	5.267
1992	1.646
1993	4.269
1994	4.667
1995	4.678
1996	4.361
1997	4.954
1998	5.029
1999	0.427
2000	2.508
2001	1.684
2002	2.486
2003	2.711
2004	4.173
2005	4.421
2006	4.797
2007	4.564
2008	6.148
2009	3.357
2010	4.127
2011	5.204
2012	5.122
2013	6.796
2014	5.461
2015	4.857
2016	4.264
2017	4.195
2018	4.224
2019	2.217
2020	-8.738
2021	6.111
2022	3.606
2023	2.500
2024	1.600
2025	2.200
2026	2.200
2027	2.300
2028	2.300
2029	2.300