Year	Percent change (Units)
1980	33.050
1981	20.510
1982	18.300
1983	16.460
1984	11.860
1985	9.091
1986	2.682
1987	11.161
1988	3.192
1989	12.250
1990	8.483
1991	-1.820
1992	9.034
1993	1.709
1994	12.087
1995	-2.926
1996	5.418
1997	6.900
1998	5.400
1999	0.373
2000	-0.165
2001	1.891
2002	7.430
2003	4.367
2004	7.847
2005	7.821
2006	3.231
2007	4.482
2008	6.267
2009	14.642
2010	-0.201
2011	2.875
2012	6.191
2013	-0.207
2014	-1.238
2015	1.923
2016	0.073
2017	1.346
2018	3.683
2019	2.189
2020	1.480
2021	-3.010
2022	8.747
2023	11.981
2024	3.563
2025	3.335
2026	3.000
2027	3.000
2028	3.000
2029	3.000