Year	Percent change (Units)
1980	1.080
1981	2.600
1982	3.191
1983	6.603
1984	7.140
1985	5.108
1986	-2.203
1987	3.377
1988	6.726
1989	0.371
1990	-3.970
1991	-5.000
1992	1.111
1993	-13.187
1994	16.709
1995	8.460
1996	4.600
1997	29.828
1998	22.533
1999	15.925
2000	21.721
2001	7.751
2002	5.929
2003	9.142
2004	18.359
2005	11.300
2006	12.657
2007	11.933
2008	-1.521
2009	-16.981
2010	9.535
2011	0.793
2012	-3.287
2013	3.377
2014	7.055
2015	13.879
2016	5.417
2017	6.718
2018	1.062
2019	4.205
2020	-1.077
2021	0.506
2022	12.035
2023	5.463
2024	3.695
2025	5.515
2026	5.500
2027	5.600
2028	5.600
2029	5.600