Year	Percent change (Units)
1980	4.426
1981	6.570
1982	5.424
1983	2.095
1984	2.882
1985	3.188
1986	0.018
1987	1.865
1988	1.970
1989	5.040
1990	5.323
1991	5.256
1992	3.454
1993	2.485
1994	0.416
1995	1.915
1996	0.752
1997	0.348
1998	-0.194
1999	1.643
2000	1.489
2001	0.332
2002	0.880
2003	0.560
2004	1.289
2005	0.975
2006	0.629
2007	2.022
2008	0.719
2009	0.296
2010	0.535
2011	-0.586
2012	-0.435
2013	0.082
2014	-0.307
2015	-1.274
2016	0.027
2017	0.878
2018	0.726
2019	0.191
2020	-0.777
2021	1.571
2022	2.877
2023	1.740
2024	1.365
2025	1.200
2026	1.245
2027	1.200
2028	1.200
2029	1.200