Year	Percent change (Units)
1980	23.930
1981	25.127
1982	296.791
1983	328.437
1984	2177.301
1985	8170.525
1986	64.647
1987	10.662
1988	21.505
1989	16.563
1990	18.010
1991	15.436
1992	10.462
1993	9.308
1994	8.523
1995	12.574
1996	7.949
1997	6.731
1998	4.395
1999	3.133
2000	3.412
2001	0.924
2002	2.448
2003	3.939
2004	4.621
2005	4.908
2006	2.990
2007	11.726
2008	11.848
2009	0.264
2010	7.182
2011	6.904
2012	4.540
2013	6.480
2014	5.194
2015	2.953
2016	4.003
2017	2.715
2018	1.507
2019	1.469
2020	0.670
2021	0.901
2022	3.123
2023	2.118
2024	4.800
2025	4.020
2026	3.927
2027	3.803
2028	3.803
2029	3.803