Year	Percent change (Units)
1980	2.910
1981	3.880
1982	2.578
1983	3.218
1984	5.303
1985	4.271
1986	5.405
1987	0.650
1988	13.169
1989	3.274
1990	4.806
1991	2.221
1992	7.096
1993	3.589
1994	-1.165
1995	6.798
1996	1.060
1997	3.741
1998	4.459
1999	2.107
2000	1.806
2001	1.607
2002	4.871
2003	6.126
2004	3.749
2005	2.269
2006	6.538
2007	3.087
2008	0.429
2009	-1.224
2010	-4.275
2011	-0.612
2012	1.052
2013	2.462
2014	1.146
2015	2.785
2016	4.150
2017	1.548
2018	3.175
2019	0.662
2020	-3.739
2021	0.754
2022	5.500
2023	6.230
2024	5.300
2025	3.900
2026	2.800
2027	2.700
2028	2.700
2029	2.700