Year	Percent change (Units)
1980	23.855
1981	13.267
1982	4.415
1983	4.228
1984	2.130
1985	2.085
1986	3.016
1987	4.816
1988	2.252
1989	7.665
1990	3.194
1991	5.556
1992	5.256
1993	1.568
1994	-0.012
1995	1.293
1996	1.701
1997	2.415
1998	0.956
1999	1.236
2000	0.848
2001	1.556
2002	0.170
2003	1.453
2004	2.394
2005	1.682
2006	2.593
2007	3.238
2008	6.360
2009	0.006
2010	2.810
2011	1.063
2012	1.357
2013	-0.046
2014	0.807
2015	-0.852
2016	0.142
2017	0.296
2018	0.989
2019	1.505
2020	-0.727
2021	1.571
2022	7.707
2023	3.463
2024	2.808
2025	2.083
2026	2.000
2027	2.000
2028	2.000
2029	2.000